20782157 has 4 divisors (see below), whose sum is σ = 22671456. Its totient is φ = 18892860.

The previous prime is 20782141. The next prime is 20782159. The reversal of 20782157 is 75128702.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 20782157 - 2⁴ = 20782141 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20782159) 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 3 ways as a sum of consecutive naturals, for example, 944633 + ... + 944654.

It is an arithmetic number, because the mean of its divisors is an integer number (5667864).

Almost surely, 2^20782157 is an apocalyptic number.

It is an amenable number.

20782157 is a deficient number, since it is larger than the sum of its proper divisors (1889299).

20782157 is a wasteful number, since it uses less digits than its factorization.

20782157 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1889298.

The product of its (nonzero) digits is 7840, while the sum is 32.

The square root of 20782157 is about 4558.7451124185. The cubic root of 20782157 is about 274.9351119632.

The spelling of 20782157 in words is "twenty million, seven hundred eighty-two thousand, one hundred fifty-seven".