21604251466 has 16 divisors (see below), whose sum is σ = 37119472704. Its totient is φ = 9238061664.

The previous prime is 21604251451. The next prime is 21604251469. The reversal of 21604251466 is 66415240612.

It is not an unprimeable number, because it can be changed into a prime (21604251469) 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 in 7 ways as a sum of consecutive naturals, for example, 1735515 + ... + 1747918.

It is an arithmetic number, because the mean of its divisors is an integer number (2319967044).

Almost surely, 2^21604251466 is an apocalyptic number.

21604251466 is a deficient number, since it is larger than the sum of its proper divisors (15515221238).

21604251466 is a wasteful number, since it uses less digits than its factorization.

21604251466 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3483885.

The product of its (nonzero) digits is 69120, while the sum is 37.

The spelling of 21604251466 in words is "twenty-one billion, six hundred four million, two hundred fifty-one thousand, four hundred sixty-six".