15657429121 has 4 divisors (see below), whose sum is σ = 16197340500. Its totient is φ = 15117517744.

The previous prime is 15657429119. The next prime is 15657429127. The reversal of 15657429121 is 12192475651.

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 6861802896 + 8795626225 = 82836^2 + 93785^2 .

It is a cyclic number.

It is not a de Polignac number, because 15657429121 - 2¹ = 15657429119 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (15657429127) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 269955646 + ... + 269955703.

It is an arithmetic number, because the mean of its divisors is an integer number (4049335125).

Almost surely, 2^15657429121 is an apocalyptic number.

It is an amenable number.

15657429121 is a deficient number, since it is larger than the sum of its proper divisors (539911379).

15657429121 is an equidigital number, since it uses as much as digits as its factorization.

15657429121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 539911378.

The product of its digits is 151200, while the sum is 43.

The spelling of 15657429121 in words is "fifteen billion, six hundred fifty-seven million, four hundred twenty-nine thousand, one hundred twenty-one".