20777216 has 36 divisors (see below), whose sum is σ = 41765052. Its totient is φ = 10315776.

The previous prime is 20777209. The next prime is 20777231. The reversal of 20777216 is 61277702.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 12390400 + 8386816 = 3520^2 + 2896^2 .

It is a hoax number, since the sum of its digits (32) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (32).

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 70766 + ... + 71058.

Almost surely, 2^20777216 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 20777216, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (20882526).

20777216 is an abundant number, since it is smaller than the sum of its proper divisors (20987836).

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

20777216 is an equidigital number, since it uses as much as digits as its factorization.

20777216 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 586 (or 572 counting only the distinct ones).

The product of its (nonzero) digits is 8232, while the sum is 32.

The square root of 20777216 is about 4558.2031547530. The cubic root of 20777216 is about 274.9133214426.

The spelling of 20777216 in words is "twenty million, seven hundred seventy-seven thousand, two hundred sixteen".