121531257 has 36 divisors (see below), whose sum is σ = 186807660. Its totient is φ = 76043520.

The previous prime is 121531219. The next prime is 121531259. The reversal of 121531257 is 752135121.

121531257 is a `hidden beast` number, since 121 + 531 + 2 + 5 + 7 = 666.

It can be written as a sum of positive squares in 6 ways, for example, as 54110736 + 67420521 = 7356^2 + 8211^2 .

It is not a de Polignac number, because 121531257 - 2⁸ = 121531001 is a prime.

Its product of digits (2100) is a multiple of the sum of its prime divisors (350).

It is a self number, because there is not a number n which added to its sum of digits gives 121531257.

It is not an unprimeable number, because it can be changed into a prime (121531259) by changing a digit.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 438603 + ... + 438879.

Almost surely, 2^121531257 is an apocalyptic number.

It is an amenable number.

121531257 is a deficient number, since it is larger than the sum of its proper divisors (65276403).

121531257 is a wasteful number, since it uses less digits than its factorization.

121531257 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 394 (or 350 counting only the distinct ones).

The product of its digits is 2100, while the sum is 27.

The square root of 121531257 is about 11024.1215976603. The cubic root of 121531257 is about 495.3315562605.

Adding to 121531257 its reverse (752135121), we get a palindrome (873666378).

The spelling of 121531257 in words is "one hundred twenty-one million, five hundred thirty-one thousand, two hundred fifty-seven".