21590823408 has 160 divisors (see below), whose sum is σ = 71937538560. Its totient is φ = 5414599680.

The previous prime is 21590823407. The next prime is 21590823421. The reversal of 21590823408 is 80432809512.

It is a hoax number, since the sum of its digits (42) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is a self number, because there is not a number n which added to its sum of digits gives 21590823408.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21590823407) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 6466 + ... + 207902.

It is an arithmetic number, because the mean of its divisors is an integer number (449609616).

Almost surely, 2^21590823408 is an apocalyptic number.

21590823408 is a gapful number since it is divisible by the number (28) 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 21590823408, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (35968769280).

21590823408 is an abundant number, since it is smaller than the sum of its proper divisors (50346715152).

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

21590823408 is a wasteful number, since it uses less digits than its factorization.

21590823408 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 201495 (or 201489 counting only the distinct ones).

The product of its (nonzero) digits is 138240, while the sum is 42.

The spelling of 21590823408 in words is "twenty-one billion, five hundred ninety million, eight hundred twenty-three thousand, four hundred eight".