21561496 has 32 divisors (see below), whose sum is σ = 44614800. Its totient is φ = 9687040.

The previous prime is 21561481. The next prime is 21561497. The reversal of 21561496 is 69416512.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21561497) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6456 + ... + 9208.

Almost surely, 2^21561496 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 21561496, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (22307400).

21561496 is an abundant number, since it is smaller than the sum of its proper divisors (23053304).

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

21561496 is a wasteful number, since it uses less digits than its factorization.

21561496 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2859 (or 2855 counting only the distinct ones).

The product of its digits is 12960, while the sum is 34.

The square root of 21561496 is about 4643.4357969073. The cubic root of 21561496 is about 278.3297503533.

The spelling of 21561496 in words is "twenty-one million, five hundred sixty-one thousand, four hundred ninety-six".