20977920 has 144 divisors (see below), whose sum is σ = 74565120. Its totient is φ = 5584896.

The previous prime is 20977889. The next prime is 20977951. The reversal of 20977920 is 2977902.

It is an interprime number because it is at equal distance from previous prime (20977889) and next prime (20977951).

It is a tau number, because it is divible by the number of its divisors (144).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (5) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 34257 + ... + 34863.

Almost surely, 2^20977920 is an apocalyptic number.

20977920 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20977920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (37282560).

20977920 is an abundant number, since it is smaller than the sum of its proper divisors (53587200).

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

20977920 is an equidigital number, since it uses as much as digits as its factorization.

20977920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 637 (or 617 counting only the distinct ones).

The product of its (nonzero) digits is 15876, while the sum is 36.

The square root of 20977920 is about 4580.1659358587. The cubic root of 20977920 is about 275.7956900059.

The spelling of 20977920 in words is "twenty million, nine hundred seventy-seven thousand, nine hundred twenty".