157121 has 4 divisors (see below), whose sum is σ = 160512. Its totient is φ = 153732.

The previous prime is 157109. The next prime is 157127. The reversal of 157121 is 121751.

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, and also an emirpimes, since its reverse is a distinct semiprime: 121751 = 7 ⋅17393.

It is a cyclic number.

It is not a de Polignac number, because 157121 - 2⁶ = 157057 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 157121.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (157127) 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, 1625 + ... + 1718.

It is an arithmetic number, because the mean of its divisors is an integer number (40128).

2¹⁵⁷¹²¹ is an apocalyptic number.

It is an amenable number.

157121 is a deficient number, since it is larger than the sum of its proper divisors (3391).

157121 is an equidigital number, since it uses as much as digits as its factorization.

157121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3390.

The product of its digits is 70, while the sum is 17.

The square root of 157121 is about 396.3849139410. The cubic root of 157121 is about 53.9607625341.

Adding to 157121 its reverse (121751), we get a palindrome (278872).

The spelling of 157121 in words is "one hundred fifty-seven thousand, one hundred twenty-one".