21261650473820 has 48 divisors (see below), whose sum is σ = 45543218208768. Its totient is φ = 8336035310400.

The previous prime is 21261650473807. The next prime is 21261650473849. The reversal of 21261650473820 is 2837405616212.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 50215256 + ... + 50636895.

It is an arithmetic number, because the mean of its divisors is an integer number (948817046016).

Almost surely, 2^{21261650473820} is an apocalyptic number.

21261650473820 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21261650473820 is an abundant number, since it is smaller than the sum of its proper divisors (24281567734948).

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

21261650473820 is a wasteful number, since it uses less digits than its factorization.

21261650473820 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 100852370 (or 100852368 counting only the distinct ones).

The product of its (nonzero) digits is 967680, while the sum is 47.

The spelling of 21261650473820 in words is "twenty-one trillion, two hundred sixty-one billion, six hundred fifty million, four hundred seventy-three thousand, eight hundred twenty".