21640204700740 has 12 divisors (see below), whose sum is σ = 45444429871596. Its totient is φ = 8656081880288.

The previous prime is 21640204700693. The next prime is 21640204700743. The reversal of 21640204700740 is 4700740204612.

It can be written as a sum of positive squares in 2 ways, for example, as 10413322473024 + 11226882227716 = 3226968^2 + 3350654^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 21640204700740.

It is not an unprimeable number, because it can be changed into a prime (21640204700743) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 541005117499 + ... + 541005117538.

It is an arithmetic number, because the mean of its divisors is an integer number (3787035822633).

Almost surely, 2^{21640204700740} is an apocalyptic number.

21640204700740 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21640204700740 is an abundant number, since it is smaller than the sum of its proper divisors (23804225170856).

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

21640204700740 is a wasteful number, since it uses less digits than its factorization.

21640204700740 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1082010235046 (or 1082010235044 counting only the distinct ones).

The product of its (nonzero) digits is 75264, while the sum is 37.

The spelling of 21640204700740 in words is "twenty-one trillion, six hundred forty billion, two hundred four million, seven hundred thousand, seven hundred forty".