21913809984 has 448 divisors, whose sum is σ = 73021301760. Its totient is φ = 6466521600.

The previous prime is 21913809979. The next prime is 21913810003. The reversal of 21913809984 is 48990831912.

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 21913809984.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 66204699 + ... + 66205029.

Almost surely, 2^21913809984 is an apocalyptic number.

21913809984 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 21913809984, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (36510650880).

21913809984 is an abundant number, since it is smaller than the sum of its proper divisors (51107491776).

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

21913809984 is an equidigital number, since it uses as much as digits as its factorization.

21913809984 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 418 (or 390 counting only the distinct ones).

The product of its (nonzero) digits is 1119744, while the sum is 54.

The spelling of 21913809984 in words is "twenty-one billion, nine hundred thirteen million, eight hundred nine thousand, nine hundred eighty-four".