20907531 has 16 divisors (see below), whose sum is σ = 31188000. Its totient is φ = 13842144.

The previous prime is 20907517. The next prime is 20907571. The reversal of 20907531 is 13570902.

It is a de Polignac number, because none of the positive numbers 2^k-20907531 is a prime.

It is a super-2 number, since 2×20907531² = 874249705031922, which 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 = 20907495 and 20907504.

It is not an unprimeable number, because it can be changed into a prime (20907571) 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, 1425 + ... + 6621.

It is an arithmetic number, because the mean of its divisors is an integer number (1949250).

Almost surely, 2^20907531 is an apocalyptic number.

20907531 is a deficient number, since it is larger than the sum of its proper divisors (10280469).

20907531 is a wasteful number, since it uses less digits than its factorization.

20907531 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5355 (or 5349 counting only the distinct ones).

The product of its (nonzero) digits is 1890, while the sum is 27.

The square root of 20907531 is about 4572.4753689878. The cubic root of 20907531 is about 275.4868774375.

The spelling of 20907531 in words is "twenty million, nine hundred seven thousand, five hundred thirty-one".