21986565120 has 792 divisors, whose sum is σ = 87839291904. Its totient is φ = 5053612032.

The previous prime is 21986565089. The next prime is 21986565131. The reversal of 21986565120 is 2156568912.

21986565120 is a `hidden beast` number, since 2 + 1 + 9 + 86 + 56 + 512 + 0 = 666.

It is a super-2 number, since 2×21986565120² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 173122497 + ... + 173122623.

Almost surely, 2^21986565120 is an apocalyptic number.

21986565120 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 21986565120, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (43919645952).

21986565120 is an abundant number, since it is smaller than the sum of its proper divisors (65852726784).

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

21986565120 is a wasteful number, since it uses less digits than its factorization.

21986565120 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 205 (or 167 counting only the distinct ones).

The product of its (nonzero) digits is 259200, while the sum is 45.

The spelling of 21986565120 in words is "twenty-one billion, nine hundred eighty-six million, five hundred sixty-five thousand, one hundred twenty".