20978886 has 32 divisors (see below), whose sum is σ = 42922368. Its totient is φ = 6834240.

The previous prime is 20978863. The next prime is 20978887. The reversal of 20978886 is 68887902.

It is a happy number.

It is a super-2 number, since 2×20978886² = 880227315601992, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20978887) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 92305 + ... + 92531.

It is an arithmetic number, because the mean of its divisors is an integer number (1341324).

Almost surely, 2^20978886 is an apocalyptic number.

20978886 is an abundant number, since it is smaller than the sum of its proper divisors (21943482).

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

20978886 is a wasteful number, since it uses less digits than its factorization.

20978886 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 516.

The product of its (nonzero) digits is 387072, while the sum is 48.

The square root of 20978886 is about 4580.2713893393. The cubic root of 20978886 is about 275.7999232592.

The spelling of 20978886 in words is "twenty million, nine hundred seventy-eight thousand, eight hundred eighty-six".