20857638 has 16 divisors (see below), whose sum is σ = 41776560. Its totient is φ = 6942336.

The previous prime is 20857631. The next prime is 20857663. The reversal of 20857638 is 83675802.

It is a junction number, because it is equal to n+sod(n) for n = 20857596 and 20857605.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20857631) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2706 + ... + 7002.

It is an arithmetic number, because the mean of its divisors is an integer number (2611035).

Almost surely, 2^20857638 is an apocalyptic number.

20857638 is an abundant number, since it is smaller than the sum of its proper divisors (20918922).

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

20857638 is a wasteful number, since it uses less digits than its factorization.

20857638 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5111.

The product of its (nonzero) digits is 80640, while the sum is 39.

The square root of 20857638 is about 4567.0163126488. The cubic root of 20857638 is about 275.2675654789.

The spelling of 20857638 in words is "twenty million, eight hundred fifty-seven thousand, six hundred thirty-eight".