21420650556 has 60 divisors (see below), whose sum is σ = 59291815968. Its totient is φ = 6720202368.

The previous prime is 21420650551. The next prime is 21420650579. The reversal of 21420650556 is 65505602412.

21420650556 is a `hidden beast` number, since 2 + 1 + 42 + 0 + 65 + 0 + 556 = 666.

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

It is a self number, because there is not a number n which added to its sum of digits gives 21420650556.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21420650551) by changing a digit.

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 19 ways as a sum of consecutive naturals, for example, 1938996 + ... + 1950011.

Almost surely, 2^21420650556 is an apocalyptic number.

It is an amenable number.

21420650556 is an abundant number, since it is smaller than the sum of its proper divisors (37871165412).

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

21420650556 is a wasteful number, since it uses less digits than its factorization.

21420650556 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3889040 (or 3889029 counting only the distinct ones).

The product of its (nonzero) digits is 72000, while the sum is 36.

The spelling of 21420650556 in words is "twenty-one billion, four hundred twenty million, six hundred fifty thousand, five hundred fifty-six".