20857315 has 16 divisors (see below), whose sum is σ = 26018496. Its totient is φ = 16038400.

The previous prime is 20857313. The next prime is 20857321. The reversal of 20857315 is 51375802.

It is not a de Polignac number, because 20857315 - 2¹ = 20857313 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20857313) 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 15 ways as a sum of consecutive naturals, for example, 13839 + ... + 15271.

It is an arithmetic number, because the mean of its divisors is an integer number (1626156).

Almost surely, 2^20857315 is an apocalyptic number.

20857315 is a deficient number, since it is larger than the sum of its proper divisors (5161181).

20857315 is a wasteful number, since it uses less digits than its factorization.

20857315 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1550.

The product of its (nonzero) digits is 8400, while the sum is 31.

The square root of 20857315 is about 4566.9809502559. The cubic root of 20857315 is about 275.2661445465.

The spelling of 20857315 in words is "twenty million, eight hundred fifty-seven thousand, three hundred fifteen".