21009305746944 has 200 divisors, whose sum is σ = 64730064028608. Its totient is φ = 6777194987520.

The previous prime is 21009305746943. The next prime is 21009305746963. The reversal of 21009305746944 is 44964750390012.

21009305746944 is a `hidden beast` number, since 2 + 1 + 0 + 0 + 9 + 3 + 0 + 574 + 69 + 4 + 4 = 666.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21009305746943) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 6885177 + ... + 9456440.

Almost surely, 2^{21009305746944} is an apocalyptic number.

21009305746944 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

21009305746944 is an abundant number, since it is smaller than the sum of its proper divisors (43720758281664).

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

21009305746944 is an equidigital number, since it uses as much as digits as its factorization.

21009305746944 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16341678 (or 16341653 counting only the distinct ones).

The product of its (nonzero) digits is 6531840, while the sum is 54.

The spelling of 21009305746944 in words is "twenty-one trillion, nine billion, three hundred five million, seven hundred forty-six thousand, nine hundred forty-four".