121221531 has 6 divisors (see below), whose sum is σ = 175097780. Its totient is φ = 80814348.

The previous prime is 121221521. The next prime is 121221533. The reversal of 121221531 is 135122121.

121221531 is a `hidden beast` number, since 12 + 122 + 1 + 531 = 666.

It is not a de Polignac number, because 121221531 - 2⁷ = 121221403 is a prime.

It is a super-2 number, since 2×121221531² = 29389319155967922, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (121221533) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 6734521 + ... + 6734538.

Almost surely, 2^121221531 is an apocalyptic number.

121221531 is a deficient number, since it is larger than the sum of its proper divisors (53876249).

121221531 is a wasteful number, since it uses less digits than its factorization.

121221531 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13469065 (or 13469062 counting only the distinct ones).

The product of its digits is 120, while the sum is 18.

The square root of 121221531 is about 11010.0649861842. The cubic root of 121221531 is about 494.9104092526.

Adding to 121221531 its reverse (135122121), we get a palindrome (256343652).

The spelling of 121221531 in words is "one hundred twenty-one million, two hundred twenty-one thousand, five hundred thirty-one".