21213600656040 has 192 divisors, whose sum is σ = 78615108608400. Its totient is φ = 4914644115456.

The previous prime is 21213600655979. The next prime is 21213600656081. The reversal of 21213600656040 is 4065600631212.

21213600656040 is a `hidden beast` number, since 2 + 1 + 2 + 1 + 3 + 600 + 6 + 5 + 6 + 0 + 40 = 666.

It can be written as a sum of positive squares in 8 ways, for example, as 2772364861764 + 18441235794276 = 1665042^2 + 4294326^2 .

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 = 21213600655986 and 21213600656004.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 133238695 + ... + 133397814.

Almost surely, 2^{21213600656040} is an apocalyptic number.

21213600656040 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21213600656040 is an abundant number, since it is smaller than the sum of its proper divisors (57401507952360).

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

21213600656040 is a wasteful number, since it uses less digits than its factorization.

21213600656040 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 266636556 (or 266636549 counting only the distinct ones).

The product of its (nonzero) digits is 51840, while the sum is 36.

The spelling of 21213600656040 in words is "twenty-one trillion, two hundred thirteen billion, six hundred million, six hundred fifty-six thousand, forty".