20782857 has 12 divisors (see below), whose sum is σ = 29437616. Its totient is φ = 13039680.

The previous prime is 20782849. The next prime is 20782877. The reversal of 20782857 is 75828702.

It is not a de Polignac number, because 20782857 - 2³ = 20782849 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20782807) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 11119 + ... + 12852.

Almost surely, 2^20782857 is an apocalyptic number.

It is an amenable number.

20782857 is a deficient number, since it is larger than the sum of its proper divisors (8654759).

20782857 is a wasteful number, since it uses less digits than its factorization.

20782857 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24008 (or 23991 counting only the distinct ones).

The product of its (nonzero) digits is 62720, while the sum is 39.

The square root of 20782857 is about 4558.8218872862. The cubic root of 20782857 is about 274.9381987845.

The spelling of 20782857 in words is "twenty million, seven hundred eighty-two thousand, eight hundred fifty-seven".