20861382531 has 16 divisors (see below), whose sum is σ = 30354842880. Its totient is φ = 12638673120.

The previous prime is 20861382527. The next prime is 20861382539. The reversal of 20861382531 is 13528316802.

It is not a de Polignac number, because 20861382531 - 2² = 20861382527 is a prime.

It is a super-2 number, since 2×20861382531² (a number of 21 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 20861382531.

It is not an unprimeable number, because it can be changed into a prime (20861382539) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 21295 + ... + 205368.

It is an arithmetic number, because the mean of its divisors is an integer number (1897177680).

Almost surely, 2^20861382531 is an apocalyptic number.

20861382531 is a deficient number, since it is larger than the sum of its proper divisors (9493460349).

20861382531 is a wasteful number, since it uses less digits than its factorization.

20861382531 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 229466.

The product of its (nonzero) digits is 69120, while the sum is 39.

The spelling of 20861382531 in words is "twenty billion, eight hundred sixty-one million, three hundred eighty-two thousand, five hundred thirty-one".