21775517440 has 72 divisors (see below), whose sum is σ = 52472014560. Its totient is φ = 8657965056.

The previous prime is 21775517431. The next prime is 21775517479. The reversal of 21775517440 is 4471557712.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 162826 + ... + 264694.

It is an arithmetic number, because the mean of its divisors is an integer number (728777980).

Almost surely, 2^21775517440 is an apocalyptic number.

21775517440 is a gapful number since it is divisible by the number (20) 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 21775517440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26236007280).

21775517440 is an abundant number, since it is smaller than the sum of its proper divisors (30696497120).

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

21775517440 is a wasteful number, since it uses less digits than its factorization.

21775517440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 102057 (or 102043 counting only the distinct ones).

The product of its (nonzero) digits is 274400, while the sum is 43.

The spelling of 21775517440 in words is "twenty-one billion, seven hundred seventy-five million, five hundred seventeen thousand, four hundred forty".