21162395520 has 384 divisors, whose sum is σ = 86215034880. Its totient is φ = 4680806400.

The previous prime is 21162395437. The next prime is 21162395531. The reversal of 21162395520 is 2559326112.

It is a happy number.

21162395520 is a `hidden beast` number, since 2 + 1 + 1 + 623 + 9 + 5 + 5 + 20 = 666.

It is a tau number, because it is divible by the number of its divisors (384).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 1241455 + ... + 1258385.

It is an arithmetic number, because the mean of its divisors is an integer number (224518320).

Almost surely, 2^21162395520 is an apocalyptic number.

21162395520 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 21162395520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (43107517440).

21162395520 is an abundant number, since it is smaller than the sum of its proper divisors (65052639360).

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

21162395520 is a wasteful number, since it uses less digits than its factorization.

21162395520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16994 (or 16979 counting only the distinct ones).

The product of its (nonzero) digits is 32400, while the sum is 36.

The spelling of 21162395520 in words is "twenty-one billion, one hundred sixty-two million, three hundred ninety-five thousand, five hundred twenty".