21423624666 has 64 divisors (see below), whose sum is σ = 45320601600. Its totient is φ = 6738088896.

The previous prime is 21423624661. The next prime is 21423624679. The reversal of 21423624666 is 66642632412.

It is a super-2 number, since 2×21423624666² (a number of 21 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21423624661) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 3133740 + ... + 3140568.

It is an arithmetic number, because the mean of its divisors is an integer number (708134400).

Almost surely, 2^21423624666 is an apocalyptic number.

21423624666 is an abundant number, since it is smaller than the sum of its proper divisors (23896976934).

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

21423624666 is a wasteful number, since it uses less digits than its factorization.

21423624666 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7163.

The product of its digits is 497664, while the sum is 42.

The spelling of 21423624666 in words is "twenty-one billion, four hundred twenty-three million, six hundred twenty-four thousand, six hundred sixty-six".