157220917 has 4 divisors (see below), whose sum is σ = 179681056. Its totient is φ = 134760780.

The previous prime is 157220911. The next prime is 157220923. The reversal of 157220917 is 719022751.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is an interprime number because it is at equal distance from previous prime (157220911) and next prime (157220923).

It is a de Polignac number, because none of the positive numbers 2^k-157220917 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 (157220911) 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, 11230059 + ... + 11230072.

It is an arithmetic number, because the mean of its divisors is an integer number (44920264).

Almost surely, 2^157220917 is an apocalyptic number.

It is an amenable number.

157220917 is a deficient number, since it is larger than the sum of its proper divisors (22460139).

157220917 is an equidigital number, since it uses as much as digits as its factorization.

157220917 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22460138.

The product of its (nonzero) digits is 8820, while the sum is 34.

The square root of 157220917 is about 12538.7765352127. The cubic root of 157220917 is about 539.7219842332.

The spelling of 157220917 in words is "one hundred fifty-seven million, two hundred twenty thousand, nine hundred seventeen".