1661923289 has 8 divisors (see below), whose sum is σ = 1800111432. Its totient is φ = 1525213440.

The previous prime is 1661923273. The next prime is 1661923301. The reversal of 1661923289 is 9823291661.

It can be written as a sum of positive squares in 4 ways, for example, as 485982025 + 1175941264 = 22045^2 + 34292^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 1661923289 - 2⁴ = 1661923273 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1661923229) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 367232 + ... + 371729.

It is an arithmetic number, because the mean of its divisors is an integer number (225013929).

Almost surely, 2^1661923289 is an apocalyptic number.

It is an amenable number.

1661923289 is a deficient number, since it is larger than the sum of its proper divisors (138188143).

1661923289 is a wasteful number, since it uses less digits than its factorization.

1661923289 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 739147.

The product of its digits is 279936, while the sum is 47.

The square root of 1661923289 is about 40766.6933782960. The cubic root of 1661923289 is about 1184.5052535383.

The spelling of 1661923289 in words is "one billion, six hundred sixty-one million, nine hundred twenty-three thousand, two hundred eighty-nine".