21577864466 has 4 divisors (see below), whose sum is σ = 32366796702. Its totient is φ = 10788932232.

The previous prime is 21577864459. The next prime is 21577864481. The reversal of 21577864466 is 66446877512.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 21003255625 + 574608841 = 144925^2 + 23971^2 .

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5394466115 + ... + 5394466118.

Almost surely, 2^21577864466 is an apocalyptic number.

21577864466 is a deficient number, since it is larger than the sum of its proper divisors (10788932236).

21577864466 is a wasteful number, since it uses less digits than its factorization.

21577864466 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10788932235.

The product of its digits is 13547520, while the sum is 56.

The spelling of 21577864466 in words is "twenty-one billion, five hundred seventy-seven million, eight hundred sixty-four thousand, four hundred sixty-six".