157687851997 has 12 divisors (see below), whose sum is σ = 170833184244. Its totient is φ = 145487746560.

The previous prime is 157687851977. The next prime is 157687852019. The reversal of 157687851997 is 799158786751.

It can be written as a sum of positive squares in 6 ways, for example, as 77991174361 + 79696677636 = 279269^2 + 282306^2 .

It is a de Polignac number, because none of the positive numbers 2^k-157687851997 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (157687851947) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 127503 + ... + 575875.

It is an arithmetic number, because the mean of its divisors is an integer number (14236098687).

Almost surely, 2^157687851997 is an apocalyptic number.

It is an amenable number.

157687851997 is a deficient number, since it is larger than the sum of its proper divisors (13145332247).

157687851997 is a wasteful number, since it uses less digits than its factorization.

157687851997 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 450480 (or 450467 counting only the distinct ones).

The product of its digits is 266716800, while the sum is 73.

The spelling of 157687851997 in words is "one hundred fifty-seven billion, six hundred eighty-seven million, eight hundred fifty-one thousand, nine hundred ninety-seven".