21351251792 has 60 divisors (see below), whose sum is σ = 45118049760. Its totient is φ = 9783356544.

The previous prime is 21351251743. The next prime is 21351251807. The reversal of 21351251792 is 29715215312.

It is a super-2 number, since 2×21351251792² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 347453 + ... + 404259.

It is an arithmetic number, because the mean of its divisors is an integer number (751967496).

Almost surely, 2^21351251792 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21351251792, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (22559024880).

21351251792 is an abundant number, since it is smaller than the sum of its proper divisors (23766797968).

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

21351251792 is a wasteful number, since it uses less digits than its factorization.

21351251792 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 56980 (or 56961 counting only the distinct ones).

The product of its digits is 37800, while the sum is 38.

The spelling of 21351251792 in words is "twenty-one billion, three hundred fifty-one million, two hundred fifty-one thousand, seven hundred ninety-two".