1689901993 has 4 divisors (see below), whose sum is σ = 1819894468. Its totient is φ = 1559909520.

The previous prime is 1689901937. The next prime is 1689902041. The reversal of 1689901993 is 3991099861.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 483868009 + 1206033984 = 21997^2 + 34728^2 .

It is a de Polignac number, because none of the positive numbers 2^k-1689901993 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1689901903) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 64996218 + ... + 64996243.

It is an arithmetic number, because the mean of its divisors is an integer number (454973617).

Almost surely, 2^1689901993 is an apocalyptic number.

1689901993 is a gapful number since it is divisible by the number (13) formed by its first and last digit.

It is an amenable number.

1689901993 is a deficient number, since it is larger than the sum of its proper divisors (129992475).

1689901993 is a wasteful number, since it uses less digits than its factorization.

1689901993 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 129992474.

The product of its (nonzero) digits is 944784, while the sum is 55.

The square root of 1689901993 is about 41108.4175443424. The cubic root of 1689901993 is about 1191.1153991293.

The spelling of 1689901993 in words is "one billion, six hundred eighty-nine million, nine hundred one thousand, nine hundred ninety-three".