21881509776 has 225 divisors, whose sum is σ = 73796982699. Its totient is φ = 6241209408.

The previous prime is 21881509759. The next prime is 21881509781. The reversal of 21881509776 is 67790518812.

The square root of 21881509776 is 147924.

It is a perfect power (a square), and thus also a powerful number.

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

It is an unprimeable number.

It is a polite number, since it can be written in 44 ways as a sum of consecutive naturals, for example, 37276555 + ... + 37277141.

Almost surely, 2^21881509776 is an apocalyptic number.

21881509776 is the 147924-th square number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21881509776

21881509776 is an abundant number, since it is smaller than the sum of its proper divisors (51915472923).

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

21881509776 is an frugal number, since it uses more digits than its factorization.

21881509776 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1208 (or 599 counting only the distinct ones).

The product of its (nonzero) digits is 1693440, while the sum is 54.

The spelling of 21881509776 in words is "twenty-one billion, eight hundred eighty-one million, five hundred nine thousand, seven hundred seventy-six".