21262408168 has 8 divisors (see below), whose sum is σ = 39867015330. Its totient is φ = 10631204080.

The previous prime is 21262408081. The next prime is 21262408169. The reversal of 21262408168 is 86180426212.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 20056790884 + 1205617284 = 141622^2 + 34722^2 .

It is a tau number, because it is divible by the number of its divisors (8).

It is a super-2 number, since 2×21262408168² (a number of 21 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21262408168.

It is not an unprimeable number, because it can be changed into a prime (21262408169) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1328900503 + ... + 1328900518.

Almost surely, 2^21262408168 is an apocalyptic number.

It is an amenable number.

21262408168 is a deficient number, since it is larger than the sum of its proper divisors (18604607162).

21262408168 is a wasteful number, since it uses less digits than its factorization.

21262408168 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2657801027 (or 2657801023 counting only the distinct ones).

The product of its (nonzero) digits is 73728, while the sum is 40.

The spelling of 21262408168 in words is "twenty-one billion, two hundred sixty-two million, four hundred eight thousand, one hundred sixty-eight".