21124420556 has 6 divisors (see below), whose sum is σ = 36967735980. Its totient is φ = 10562210276.

The previous prime is 21124420519. The next prime is 21124420567. The reversal of 21124420556 is 65502442112.

It is a super-2 number, since 2×21124420556² (a number of 21 digits) contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2640552566 + ... + 2640552573.

It is an arithmetic number, because the mean of its divisors is an integer number (6161289330).

Almost surely, 2^21124420556 is an apocalyptic number.

It is an amenable number.

21124420556 is a deficient number, since it is larger than the sum of its proper divisors (15843315424).

21124420556 is a wasteful number, since it uses less digits than its factorization.

21124420556 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5281105143 (or 5281105141 counting only the distinct ones).

The product of its (nonzero) digits is 19200, while the sum is 32.

Adding to 21124420556 its reverse (65502442112), we get a palindrome (86626862668).

The spelling of 21124420556 in words is "twenty-one billion, one hundred twenty-four million, four hundred twenty thousand, five hundred fifty-six".