21145306464 has 72 divisors (see below), whose sum is σ = 60150544272. Its totient is φ = 7046257920.

The previous prime is 21145306447. The next prime is 21145306577. The reversal of 21145306464 is 46460354112.

21145306464 is a `hidden beast` number, since 2 + 1 + 1 + 4 + 5 + 3 + 0 + 646 + 4 = 666.

It is a tau number, because it is divible by the number of its divisors (72).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1116982 + ... + 1135754.

It is an arithmetic number, because the mean of its divisors is an integer number (835424226).

Almost surely, 2^21145306464 is an apocalyptic number.

21145306464 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

21145306464 is an abundant number, since it is smaller than the sum of its proper divisors (39005237808).

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

21145306464 is a wasteful number, since it uses less digits than its factorization.

21145306464 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22700 (or 22689 counting only the distinct ones).

The product of its (nonzero) digits is 69120, while the sum is 36.

The spelling of 21145306464 in words is "twenty-one billion, one hundred forty-five million, three hundred six thousand, four hundred sixty-four".