157221139 has 4 divisors (see below), whose sum is σ = 159211360. Its totient is φ = 155230920.

The previous prime is 157221133. The next prime is 157221149. The reversal of 157221139 is 931122751.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 157221139 - 2⁷ = 157221011 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 157221139.

It is not an unprimeable number, because it can be changed into a prime (157221133) 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, 994992 + ... + 995149.

It is an arithmetic number, because the mean of its divisors is an integer number (39802840).

Almost surely, 2^157221139 is an apocalyptic number.

157221139 is a deficient number, since it is larger than the sum of its proper divisors (1990221).

157221139 is an equidigital number, since it uses as much as digits as its factorization.

157221139 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1990220.

The product of its digits is 3780, while the sum is 31.

The square root of 157221139 is about 12538.7853877479. The cubic root of 157221139 is about 539.7222382669.

It can be divided in two parts, 15722 and 1139, that added together give a palindrome (16861).

The spelling of 157221139 in words is "one hundred fifty-seven million, two hundred twenty-one thousand, one hundred thirty-nine".