20939891040 has 192 divisors, whose sum is σ = 73826665920. Its totient is φ = 5543055360.

The previous prime is 20939890997. The next prime is 20939891047. The reversal of 20939891040 is 4019893902.

20939891040 is a `hidden beast` number, since 209 + 398 + 9 + 10 + 40 = 666.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20939891047) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 574150 + ... + 609530.

It is an arithmetic number, because the mean of its divisors is an integer number (384513885).

Almost surely, 2^20939891040 is an apocalyptic number.

20939891040 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20939891040, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (36913332960).

20939891040 is an abundant number, since it is smaller than the sum of its proper divisors (52886774880).

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

20939891040 is a wasteful number, since it uses less digits than its factorization.

20939891040 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 35542 (or 35528 counting only the distinct ones).

The product of its (nonzero) digits is 139968, while the sum is 45.

The spelling of 20939891040 in words is "twenty billion, nine hundred thirty-nine million, eight hundred ninety-one thousand, forty".