20215313531 has 12 divisors (see below), whose sum is σ = 23539044672. Its totient is φ = 17310264048.

The previous prime is 20215313483. The next prime is 20215313561. The reversal of 20215313531 is 13531351202.

It is a de Polignac number, because none of the positive numbers 2^k-20215313531 is a prime.

It is a super-2 number, since 2×20215313531² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 20215313531.

It is not an unprimeable number, because it can be changed into a prime (20215313561) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 153995 + ... + 253268.

It is an arithmetic number, because the mean of its divisors is an integer number (1961587056).

Almost surely, 2^20215313531 is an apocalyptic number.

20215313531 is a deficient number, since it is larger than the sum of its proper divisors (3323731141).

20215313531 is a wasteful number, since it uses less digits than its factorization.

20215313531 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 408290 (or 408283 counting only the distinct ones).

The product of its (nonzero) digits is 2700, while the sum is 26.

Adding to 20215313531 its reverse (13531351202), we get a palindrome (33746664733).

The spelling of 20215313531 in words is "twenty billion, two hundred fifteen million, three hundred thirteen thousand, five hundred thirty-one".