21421626520 has 64 divisors (see below), whose sum is σ = 55169786880. Its totient is φ = 7333143936.

The previous prime is 21421626503. The next prime is 21421626521. The reversal of 21421626520 is 2562612412.

It is a super-3 number, since 3×21421626520³ (a number of 32 digits) contains 333 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21421626521) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 122037 + ... + 240283.

It is an arithmetic number, because the mean of its divisors is an integer number (862027920).

Almost surely, 2^21421626520 is an apocalyptic number.

21421626520 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 21421626520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27584893440).

21421626520 is an abundant number, since it is smaller than the sum of its proper divisors (33748160360).

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

21421626520 is a wasteful number, since it uses less digits than its factorization.

21421626520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 118912 (or 118908 counting only the distinct ones).

The product of its (nonzero) digits is 11520, while the sum is 31.

The spelling of 21421626520 in words is "twenty-one billion, four hundred twenty-one million, six hundred twenty-six thousand, five hundred twenty".