157721537 has 8 divisors (see below), whose sum is σ = 160124160. Its totient is φ = 155325600.

The previous prime is 157721507. The next prime is 157721561. The reversal of 157721537 is 735127751.

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 157721537 - 2¹⁰ = 157720513 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 157721537.

It is not an unprimeable number, because it can be changed into a prime (157721507) 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 7 ways as a sum of consecutive naturals, for example, 65912 + ... + 68262.

It is an arithmetic number, because the mean of its divisors is an integer number (20015520).

Almost surely, 2^157721537 is an apocalyptic number.

It is an amenable number.

157721537 is a deficient number, since it is larger than the sum of its proper divisors (2402623).

157721537 is an equidigital number, since it uses as much as digits as its factorization.

157721537 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3343.

The product of its digits is 51450, while the sum is 38.

The square root of 157721537 is about 12558.7235418254. The cubic root of 157721537 is about 540.2942349386.

The spelling of 157721537 in words is "one hundred fifty-seven million, seven hundred twenty-one thousand, five hundred thirty-seven".