20749263440 has 20 divisors (see below), whose sum is σ = 48242037684. Its totient is φ = 8299705344.

The previous prime is 20749263439. The next prime is 20749263497. The reversal of 20749263440 is 4436294702.

It can be written as a sum of positive squares in 2 ways, for example, as 4527674944 + 16221588496 = 67288^2 + 127364^2 .

It is a tau number, because it is divible by the number of its divisors (20).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 129682817 + ... + 129682976.

Almost surely, 2^20749263440 is an apocalyptic number.

20749263440 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20749263440 is an abundant number, since it is smaller than the sum of its proper divisors (27492774244).

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

20749263440 is a wasteful number, since it uses less digits than its factorization.

20749263440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 259365806 (or 259365800 counting only the distinct ones).

The product of its (nonzero) digits is 290304, while the sum is 41.

The spelling of 20749263440 in words is "twenty billion, seven hundred forty-nine million, two hundred sixty-three thousand, four hundred forty".