20777856 has 64 divisors (see below), whose sum is σ = 60220800. Its totient is φ = 6295040.

The previous prime is 20777837. The next prime is 20777899. The reversal of 20777856 is 65877702.

It is a tau number, because it is divible by the number of its divisors (64).

It is a Smith number, since the sum of its digits (42) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1765 + ... + 6683.

It is an arithmetic number, because the mean of its divisors is an integer number (940950).

Almost surely, 2^20777856 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 20777856, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30110400).

20777856 is an abundant number, since it is smaller than the sum of its proper divisors (39442944).

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

20777856 is a wasteful number, since it uses less digits than its factorization.

20777856 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4947 (or 4935 counting only the distinct ones).

The product of its (nonzero) digits is 164640, while the sum is 42.

The square root of 20777856 is about 4558.2733573141. The cubic root of 20777856 is about 274.9161441294.

The spelling of 20777856 in words is "twenty million, seven hundred seventy-seven thousand, eight hundred fifty-six".