20779920 has 360 divisors, whose sum is σ = 88208640. Its totient is φ = 4354560.

The previous prime is 20779919. The next prime is 20779937. The reversal of 20779920 is 2997702.

It is a tau number, because it is divible by the number of its divisors (360).

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

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 670305 + ... + 670335.

It is an arithmetic number, because the mean of its divisors is an integer number (245024).

Almost surely, 2^20779920 is an apocalyptic number.

20779920 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 20779920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (44104320).

20779920 is an abundant number, since it is smaller than the sum of its proper divisors (67428720).

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

20779920 is a wasteful number, since it uses less digits than its factorization.

20779920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 83 (or 67 counting only the distinct ones).

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

The square root of 20779920 is about 4558.4997532083. The cubic root of 20779920 is about 274.9252468994.

The spelling of 20779920 in words is "twenty million, seven hundred seventy-nine thousand, nine hundred twenty".