1691430129 has 9 divisors (see below), whose sum is σ = 2443355083. Its totient is φ = 1127537832.

The previous prime is 1691430127. The next prime is 1691430131. The reversal of 1691430129 is 9210341961.

It is a happy number.

The square root of 1691430129 is 41127.

It is a perfect power (a square), and thus also a powerful number.

1691430129 is a `hidden beast` number, since 16 + 91 + 430 + 129 = 666.

It is an interprime number because it is at equal distance from previous prime (1691430127) and next prime (1691430131).

It can be written as a sum of positive squares in only one way, i.e., 1460997729 + 230432400 = 38223^2 + 15180^2 .

It is a tau number, because it is divible by the number of its divisors (9).

It is not a de Polignac number, because 1691430129 - 2¹ = 1691430127 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 1691430093 and 1691430102.

It is not an unprimeable number, because it can be changed into a prime (1691430127) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 116527 + ... + 130235.

Almost surely, 2^1691430129 is an apocalyptic number.

1691430129 is the 41127-th square number.

1691430129 is the 20564-th centered octagonal number.

It is an amenable number.

1691430129 is a deficient number, since it is larger than the sum of its proper divisors (751924954).

1691430129 is an frugal number, since it uses more digits than its factorization.

1691430129 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27424 (or 13712 counting only the distinct ones).

The product of its (nonzero) digits is 11664, while the sum is 36.

The cubic root of 1691430129 is about 1191.4743228923.

Multiplying 1691430129 by its sum of digits (36), we get a square (60891484644 = 246762²).

Multiplying 1691430129 by its product of nonzero digits (11664), we get a square (19728841024656 = 4441716²).

The spelling of 1691430129 in words is "one billion, six hundred ninety-one million, four hundred thirty thousand, one hundred twenty-nine".