20938531640 has 32 divisors (see below), whose sum is σ = 50735674080. Its totient is φ = 7731149952.

The previous prime is 20938531633. The next prime is 20938531651. The reversal of 20938531640 is 4613583902.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 20132684 + ... + 20133723.

It is an arithmetic number, because the mean of its divisors is an integer number (1585489815).

Almost surely, 2^20938531640 is an apocalyptic number.

20938531640 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20938531640 is an abundant number, since it is smaller than the sum of its proper divisors (29797142440).

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

20938531640 is a wasteful number, since it uses less digits than its factorization.

20938531640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 40266431 (or 40266427 counting only the distinct ones).

The product of its (nonzero) digits is 155520, while the sum is 41.

The spelling of 20938531640 in words is "twenty billion, nine hundred thirty-eight million, five hundred thirty-one thousand, six hundred forty".