21019973721700 has 36 divisors (see below), whose sum is σ = 46064960255412. Its totient is φ = 8324742064000.

The previous prime is 21019973721679. The next prime is 21019973721709. The reversal of 21019973721700 is 712737991012.

It is a happy number.

It can be written as a sum of positive squares in 6 ways, for example, as 3656684764516 + 17363288957184 = 1912246^2 + 4166928^2 .

It is a super-5 number, since 5×21019973721700⁵ (a number of 68 digits) contains 55555 as substring.

It is not an unprimeable number, because it can be changed into a prime (21019973721709) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1040582659 + ... + 1040602858.

It is an arithmetic number, because the mean of its divisors is an integer number (1279582229317).

Almost surely, 2^{21019973721700} is an apocalyptic number.

21019973721700 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21019973721700 is an abundant number, since it is smaller than the sum of its proper divisors (25044986533712).

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

21019973721700 is a wasteful number, since it uses less digits than its factorization.

21019973721700 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2081185632 (or 2081185625 counting only the distinct ones).

The product of its (nonzero) digits is 333396, while the sum is 49.

The spelling of 21019973721700 in words is "twenty-one trillion, nineteen billion, nine hundred seventy-three million, seven hundred twenty-one thousand, seven hundred".