20782057 has 4 divisors (see below), whose sum is σ = 20800836. Its totient is φ = 20763280.

The previous prime is 20782051. The next prime is 20782061. The reversal of 20782057 is 75028702.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 9024016 + 11758041 = 3004^2 + 3429^2 .

It is a cyclic number.

It is not a de Polignac number, because 20782057 - 2²³ = 12393449 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20782051) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 7618 + ... + 9979.

It is an arithmetic number, because the mean of its divisors is an integer number (5200209).

Almost surely, 2^20782057 is an apocalyptic number.

It is an amenable number.

20782057 is a deficient number, since it is larger than the sum of its proper divisors (18779).

20782057 is a wasteful number, since it uses less digits than its factorization.

20782057 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18778.

The product of its (nonzero) digits is 7840, while the sum is 31.

The square root of 20782057 is about 4558.7341444748. The cubic root of 20782057 is about 274.9346709830.

The spelling of 20782057 in words is "twenty million, seven hundred eighty-two thousand, fifty-seven".