21202487640 has 64 divisors (see below), whose sum is σ = 70674962400. Its totient is φ = 5653996416.

The previous prime is 21202487639. The next prime is 21202487651. The reversal of 21202487640 is 4678420212.

21202487640 is a `hidden beast` number, since 2 + 1 + 2 + 0 + 2 + 4 + 8 + 7 + 640 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 21202487595 and 21202487604.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 9814887 + ... + 9817046.

Almost surely, 2^21202487640 is an apocalyptic number.

21202487640 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21202487640 is an abundant number, since it is smaller than the sum of its proper divisors (49472474760).

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

21202487640 is a wasteful number, since it uses less digits than its factorization.

21202487640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19631953 (or 19631943 counting only the distinct ones).

The product of its (nonzero) digits is 43008, while the sum is 36.

The spelling of 21202487640 in words is "twenty-one billion, two hundred two million, four hundred eighty-seven thousand, six hundred forty".