20978464 has 48 divisors (see below), whose sum is σ = 44876160. Its totient is φ = 9596160.

The previous prime is 20978431. The next prime is 20978473. The reversal of 20978464 is 46487902.

It is an unprimeable number.

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, 87657 + ... + 87895.

It is an arithmetic number, because the mean of its divisors is an integer number (934920).

Almost surely, 2^20978464 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 20978464, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (22438080).

20978464 is an abundant number, since it is smaller than the sum of its proper divisors (23897696).

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

20978464 is a wasteful number, since it uses less digits than its factorization.

20978464 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 473 (or 465 counting only the distinct ones).

The product of its (nonzero) digits is 96768, while the sum is 40.

The square root of 20978464 is about 4580.2253219683. The cubic root of 20978464 is about 275.7980739658.

The spelling of 20978464 in words is "twenty million, nine hundred seventy-eight thousand, four hundred sixty-four".