20397959840 has 48 divisors (see below), whose sum is σ = 48731676840. Its totient is φ = 8067502080.

The previous prime is 20397959819. The next prime is 20397959849. The reversal of 20397959840 is 4895979302.

It can be written as a sum of positive squares in 4 ways, for example, as 18899650576 + 1498309264 = 137476^2 + 38708^2 .

It is not an unprimeable number, because it can be changed into a prime (20397959849) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 701981 + ... + 730460.

Almost surely, 2^20397959840 is an apocalyptic number.

20397959840 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20397959840 is an abundant number, since it is smaller than the sum of its proper divisors (28333717000).

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

20397959840 is a wasteful number, since it uses less digits than its factorization.

20397959840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1432545 (or 1432537 counting only the distinct ones).

The product of its (nonzero) digits is 4898880, while the sum is 56.

The spelling of 20397959840 in words is "twenty billion, three hundred ninety-seven million, nine hundred fifty-nine thousand, eight hundred forty".