21195371520 has 704 divisors, whose sum is σ = 82770854400. Its totient is φ = 5119672320.

The previous prime is 21195371479. The next prime is 21195371551. The reversal of 21195371520 is 2517359112.

21195371520 is a `hidden beast` number, since 2 + 1 + 19 + 53 + 71 + 520 = 666.

It is a super-2 number, since 2×21195371520² (a number of 21 digits) contains 22 as substring.

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

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 68152165 + ... + 68152475.

Almost surely, 2^21195371520 is an apocalyptic number.

21195371520 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 21195371520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (41385427200).

21195371520 is an abundant number, since it is smaller than the sum of its proper divisors (61575482880).

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

21195371520 is a wasteful number, since it uses less digits than its factorization.

21195371520 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 391 (or 367 counting only the distinct ones).

The product of its (nonzero) digits is 18900, while the sum is 36.

The spelling of 21195371520 in words is "twenty-one billion, one hundred ninety-five million, three hundred seventy-one thousand, five hundred twenty".