20857455 has 24 divisors (see below), whose sum is σ = 37132992. Its totient is φ = 10822464.

The previous prime is 20857429. The next prime is 20857469. The reversal of 20857455 is 55475802.

It is a happy number.

It is not a de Polignac number, because 20857455 - 2¹³ = 20849263 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 4599 + ... + 7928.

It is an arithmetic number, because the mean of its divisors is an integer number (1547208).

Almost surely, 2^20857455 is an apocalyptic number.

20857455 is a deficient number, since it is larger than the sum of its proper divisors (16275537).

20857455 is a wasteful number, since it uses less digits than its factorization.

20857455 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12575 (or 12572 counting only the distinct ones).

The product of its (nonzero) digits is 56000, while the sum is 36.

The square root of 20857455 is about 4566.9962776425. The cubic root of 20857455 is about 275.2667604323.

It can be divided in two parts, 20857 and 455, that added together give a palindrome (21312).

The spelling of 20857455 in words is "twenty million, eight hundred fifty-seven thousand, four hundred fifty-five".