20780556 has 24 divisors (see below), whose sum is σ = 48590640. Its totient is φ = 6912192.

The previous prime is 20780549. The next prime is 20780581. The reversal of 20780556 is 65508702.

It is a happy 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 7 ways as a sum of consecutive naturals, for example, 5130 + ... + 8238.

It is an arithmetic number, because the mean of its divisors is an integer number (2024610).

Almost surely, 2^20780556 is an apocalyptic number.

It is an amenable number.

20780556 is an abundant number, since it is smaller than the sum of its proper divisors (27810084).

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

20780556 is a wasteful number, since it uses less digits than its factorization.

20780556 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3673 (or 3671 counting only the distinct ones).

The product of its (nonzero) digits is 16800, while the sum is 33.

The square root of 20780556 is about 4558.5695124677. The cubic root of 20780556 is about 274.9280517012.

The spelling of 20780556 in words is "twenty million, seven hundred eighty thousand, five hundred fifty-six".