21984677643456 has 560 divisors, whose sum is σ = 79237926725760. Its totient is φ = 5940127457280.

The previous prime is 21984677643431. The next prime is 21984677643571. The reversal of 21984677643456 is 65434677648912.

21984677643456 is a `hidden beast` number, since 2 + 1 + 9 + 8 + 4 + 67 + 76 + 43 + 456 = 666.

It is a super-2 number, since 2×21984677643456² (a number of 27 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (72).

It is an unprimeable number.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 17821951 + ... + 19015553.

Almost surely, 2^{21984677643456} is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21984677643456, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (39618963362880).

21984677643456 is an abundant number, since it is smaller than the sum of its proper divisors (57253249082304).

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

21984677643456 is a wasteful number, since it uses less digits than its factorization.

21984677643456 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1193674 (or 1193655 counting only the distinct ones).

The product of its digits is 1463132160, while the sum is 72.

The spelling of 21984677643456 in words is "twenty-one trillion, nine hundred eighty-four billion, six hundred seventy-seven million, six hundred forty-three thousand, four hundred fifty-six".