21506205145464 has 48 divisors (see below), whose sum is σ = 62726431677000. Its totient is φ = 6617293890624.

The previous prime is 21506205145457. The next prime is 21506205145531. The reversal of 21506205145464 is 46454150260512.

21506205145464 is a `hidden beast` number, since 2 + 1 + 5 + 0 + 6 + 20 + 514 + 54 + 64 = 666.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 11488356514 + ... + 11488358385.

Almost surely, 2^{21506205145464} is an apocalyptic number.

21506205145464 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

21506205145464 is an abundant number, since it is smaller than the sum of its proper divisors (41220226531536).

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

21506205145464 is a wasteful number, since it uses less digits than its factorization.

21506205145464 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22976714924 (or 22976714917 counting only the distinct ones).

The product of its (nonzero) digits is 1152000, while the sum is 45.

The spelling of 21506205145464 in words is "twenty-one trillion, five hundred six billion, two hundred five million, one hundred forty-five thousand, four hundred sixty-four".