21154974984 has 768 divisors, whose sum is σ = 76416480000. Its totient is φ = 5364817920.

The previous prime is 21154974961. The next prime is 21154975007. The reversal of 21154974984 is 48947945112.

21154974984 is a `hidden beast` number, since 2 + 1 + 1 + 549 + 7 + 4 + 98 + 4 = 666.

It is an interprime number because it is at equal distance from previous prime (21154974961) and next prime (21154975007).

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

It is a self number, because there is not a number n which added to its sum of digits gives 21154974984.

It is an unprimeable number.

It is a polite number, since it can be written in 191 ways as a sum of consecutive naturals, for example, 187212112 + ... + 187212224.

It is an arithmetic number, because the mean of its divisors is an integer number (99500625).

Almost surely, 2^21154974984 is an apocalyptic number.

21154974984 is a gapful number since it is divisible by the number (24) 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 21154974984, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (38208240000).

21154974984 is an abundant number, since it is smaller than the sum of its proper divisors (55261505016).

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

21154974984 is a wasteful number, since it uses less digits than its factorization.

21154974984 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 211 (or 190 counting only the distinct ones).

The product of its digits is 2903040, while the sum is 54.

The spelling of 21154974984 in words is "twenty-one billion, one hundred fifty-four million, nine hundred seventy-four thousand, nine hundred eighty-four".