12121605531 has 40 divisors (see below), whose sum is σ = 20887891200. Its totient is φ = 6861862512.

The previous prime is 12121605491. The next prime is 12121605533. The reversal of 12121605531 is 13550612121.

12121605531 is a `hidden beast` number, since 1 + 2 + 1 + 2 + 1 + 605 + 53 + 1 = 666.

It is not a de Polignac number, because 12121605531 - 2⁷ = 12121605403 is a prime.

It is a super-2 number, since 2×12121605531² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a junction number, because it is equal to n+sod(n) for n = 12121605495 and 12121605504.

It is not an unprimeable number, because it can be changed into a prime (12121605533) by changing a digit.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 39231 + ... + 160568.

It is an arithmetic number, because the mean of its divisors is an integer number (522197280).

Almost surely, 2^12121605531 is an apocalyptic number.

12121605531 is a deficient number, since it is larger than the sum of its proper divisors (8766285669).

12121605531 is a wasteful number, since it uses less digits than its factorization.

12121605531 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 199925 (or 199916 counting only the distinct ones).

The product of its (nonzero) digits is 1800, while the sum is 27.

The spelling of 12121605531 in words is "twelve billion, one hundred twenty-one million, six hundred five thousand, five hundred thirty-one".