20987456 has 56 divisors (see below), whose sum is σ = 48280320. Its totient is φ = 8865792.

The previous prime is 20987453. The next prime is 20987479. The reversal of 20987456 is 65478902.

It is a tau number, because it is divible by the number of its divisors (56).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20987453) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 35096 + ... + 35688.

Almost surely, 2^20987456 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 20987456, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24140160).

20987456 is an abundant number, since it is smaller than the sum of its proper divisors (27292864).

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

20987456 is an equidigital number, since it uses as much as digits as its factorization.

20987456 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 691 (or 681 counting only the distinct ones).

The product of its (nonzero) digits is 120960, while the sum is 41.

The square root of 20987456 is about 4581.2068279003. The cubic root of 20987456 is about 275.8374734508.

The spelling of 20987456 in words is "twenty million, nine hundred eighty-seven thousand, four hundred fifty-six".