21995681051520 has 1280 divisors, whose sum is σ = 87333966720000. Its totient is φ = 5231008235520.

The previous prime is 21995681051483. The next prime is 21995681051579. The reversal of 21995681051520 is 2515018659912.

21995681051520 is a `hidden beast` number, since 2 + 1 + 9 + 9 + 5 + 6 + 8 + 105 + 1 + 520 = 666.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 159 ways as a sum of consecutive naturals, for example, 7052156521 + ... + 7052159639.

It is an arithmetic number, because the mean of its divisors is an integer number (68229661500).

Almost surely, 2^{21995681051520} is an apocalyptic number.

21995681051520 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 21995681051520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (43666983360000).

21995681051520 is an abundant number, since it is smaller than the sum of its proper divisors (65338285668480).

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

21995681051520 is a wasteful number, since it uses less digits than its factorization.

21995681051520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3393 (or 3372 counting only the distinct ones).

The product of its (nonzero) digits is 1944000, while the sum is 54.

The spelling of 21995681051520 in words is "twenty-one trillion, nine hundred ninety-five billion, six hundred eighty-one million, fifty-one thousand, five hundred twenty".