21075904040 has 32 divisors (see below), whose sum is σ = 48577392360. Its totient is φ = 8224742400.

The previous prime is 21075904021. The next prime is 21075904097. The reversal of 21075904040 is 4040957012.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 13675431364 + 7400472676 = 116942^2 + 86026^2 .

It is a super-2 number, since 2×21075904040² (a number of 21 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21075903988 and 21075904006.

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, 6423941 + ... + 6427220.

Almost surely, 2^21075904040 is an apocalyptic number.

21075904040 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21075904040 is an abundant number, since it is smaller than the sum of its proper divisors (27501488320).

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

21075904040 is a wasteful number, since it uses less digits than its factorization.

21075904040 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12851213 (or 12851209 counting only the distinct ones).

The product of its (nonzero) digits is 10080, while the sum is 32.

The spelling of 21075904040 in words is "twenty-one billion, seventy-five million, nine hundred four thousand, forty".