20931534 has 48 divisors (see below), whose sum is σ = 50664432. Its totient is φ = 6438528.

The previous prime is 20931523. The next prime is 20931551. The reversal of 20931534 is 43513902.

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 = 20931498 and 20931507.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 4662 + ... + 7974.

It is an arithmetic number, because the mean of its divisors is an integer number (1055509).

Almost surely, 2^20931534 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20931534, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25332216).

20931534 is an abundant number, since it is smaller than the sum of its proper divisors (29732898).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

20931534 is a wasteful number, since it uses less digits than its factorization.

20931534 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3343 (or 3331 counting only the distinct ones).

The product of its (nonzero) digits is 3240, while the sum is 27.

The square root of 20931534 is about 4575.0993431837. The cubic root of 20931534 is about 275.5922618342.

The spelling of 20931534 in words is "twenty million, nine hundred thirty-one thousand, five hundred thirty-four".