21274100820 has 336 divisors, whose sum is σ = 77871265920. Its totient is φ = 4778880768.

The previous prime is 21274100777. The next prime is 21274100873. The reversal of 21274100820 is 2800147212.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 111 ways as a sum of consecutive naturals, for example, 6019774 + ... + 6023306.

It is an arithmetic number, because the mean of its divisors is an integer number (231759720).

Almost surely, 2^21274100820 is an apocalyptic number.

21274100820 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21274100820, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (38935632960).

21274100820 is an abundant number, since it is smaller than the sum of its proper divisors (56597165100).

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

21274100820 is a wasteful number, since it uses less digits than its factorization.

21274100820 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3626 (or 3609 counting only the distinct ones).

The product of its (nonzero) digits is 1792, while the sum is 27.

The spelling of 21274100820 in words is "twenty-one billion, two hundred seventy-four million, one hundred thousand, eight hundred twenty".