20791450640 has 20 divisors (see below), whose sum is σ = 48340122924. Its totient is φ = 8316580224.

The previous prime is 20791450607. The next prime is 20791450651. The reversal of 20791450640 is 4605419702.

It can be written as a sum of positive squares in 2 ways, for example, as 4151482624 + 16639968016 = 64432^2 + 128996^2 .

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

It is a junction number, because it is equal to n+sod(n) for n = 20791450594 and 20791450603.

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, 129946487 + ... + 129946646.

Almost surely, 2^20791450640 is an apocalyptic number.

20791450640 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20791450640 is an abundant number, since it is smaller than the sum of its proper divisors (27548672284).

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

20791450640 is a wasteful number, since it uses less digits than its factorization.

20791450640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 259893146 (or 259893140 counting only the distinct ones).

The product of its (nonzero) digits is 60480, while the sum is 38.

The spelling of 20791450640 in words is "twenty billion, seven hundred ninety-one million, four hundred fifty thousand, six hundred forty".