121656531 has 4 divisors (see below), whose sum is σ = 162208712. Its totient is φ = 81104352.

The previous prime is 121656529. The next prime is 121656533. The reversal of 121656531 is 135656121.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 135656121 = 3 ⋅45218707.

It is an interprime number because it is at equal distance from previous prime (121656529) and next prime (121656533).

It is not a de Polignac number, because 121656531 - 2¹ = 121656529 is a prime.

It is a super-2 number, since 2×121656531² = 29600623069907922, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (121656533) 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, 20276086 + ... + 20276091.

It is an arithmetic number, because the mean of its divisors is an integer number (40552178).

Almost surely, 2^121656531 is an apocalyptic number.

121656531 is a deficient number, since it is larger than the sum of its proper divisors (40552181).

121656531 is an equidigital number, since it uses as much as digits as its factorization.

121656531 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 40552180.

The product of its digits is 5400, while the sum is 30.

The square root of 121656531 is about 11029.8019474513. The cubic root of 121656531 is about 495.5016931675.

The spelling of 121656531 in words is "one hundred twenty-one million, six hundred fifty-six thousand, five hundred thirty-one".