21901780992 has 384 divisors, whose sum is σ = 73617223680. Its totient is φ = 5635768320.

The previous prime is 21901780987. The next prime is 21901780997. The reversal of 21901780992 is 29908710912.

It is an interprime number because it is at equal distance from previous prime (21901780987) and next prime (21901780997).

It is a tau number, because it is divible by the number of its divisors (384).

It is a Harshad number since it is a multiple of its sum of digits (48).

It is not an unprimeable number, because it can be changed into a prime (21901780997) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 24041017 + ... + 24041927.

It is an arithmetic number, because the mean of its divisors is an integer number (191711520).

Almost surely, 2^21901780992 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 21901780992, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (36808611840).

21901780992 is an abundant number, since it is smaller than the sum of its proper divisors (51715442688).

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

21901780992 is a wasteful number, since it uses less digits than its factorization.

21901780992 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 999 (or 979 counting only the distinct ones).

The product of its (nonzero) digits is 163296, while the sum is 48.

The spelling of 21901780992 in words is "twenty-one billion, nine hundred one million, seven hundred eighty thousand, nine hundred ninety-two".