20978560 has 32 divisors (see below), whose sum is σ = 50153400. Its totient is φ = 8391168.

The previous prime is 20978557. The next prime is 20978567. The reversal of 20978560 is 6587902.

It is a tau number, because it is divible by the number of its divisors (32).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20978567) 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 3 ways as a sum of consecutive naturals, for example, 15750 + ... + 17029.

Almost surely, 2^20978560 is an apocalyptic number.

20978560 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20978560 is an abundant number, since it is smaller than the sum of its proper divisors (29174840).

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

20978560 is an equidigital number, since it uses as much as digits as its factorization.

20978560 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 32798 (or 32786 counting only the distinct ones).

The product of its (nonzero) digits is 30240, while the sum is 37.

The square root of 20978560 is about 4580.2358017901. The cubic root of 20978560 is about 275.7984946603.

The spelling of 20978560 in words is "twenty million, nine hundred seventy-eight thousand, five hundred sixty".