157221 has 12 divisors (see below), whose sum is σ = 235872. Its totient is φ = 104652.

The previous prime is 157219. The next prime is 157229. The reversal of 157221 is 122751.

It is not a de Polignac number, because 157221 - 2¹ = 157219 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 157194 and 157203.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 157221.

It is not an unprimeable number, because it can be changed into a prime (157229) 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, 81 + ... + 566.

It is an arithmetic number, because the mean of its divisors is an integer number (19656).

2¹⁵⁷²²¹ is an apocalyptic number.

It is an amenable number.

157221 is a deficient number, since it is larger than the sum of its proper divisors (78651).

157221 is an frugal number, since it uses more digits than its factorization.

157221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 662 (or 650 counting only the distinct ones).

The product of its digits is 140, while the sum is 18.

The square root of 157221 is about 396.5110338944. The cubic root of 157221 is about 53.9722079210.

Adding to 157221 its reverse (122751), we get a palindrome (279972).

It can be divided in two parts, 157 and 221, that added together give a triangular number (378 = T₂₇).

The spelling of 157221 in words is "one hundred fifty-seven thousand, two hundred twenty-one".