20856297 has 64 divisors (see below), whose sum is σ = 37822464. Its totient is φ = 9891840.

The previous prime is 20856259. The next prime is 20856317. The reversal of 20856297 is 79265802.

It is a happy number.

It is not a de Polignac number, because 20856297 - 2⁸ = 20856041 is a prime.

It is not an unprimeable number, because it can be changed into a prime (20852297) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 184513 + ... + 184625.

It is an arithmetic number, because the mean of its divisors is an integer number (590976).

Almost surely, 2^20856297 is an apocalyptic number.

20856297 is the 3729-th pentagonal number.

It is an amenable number.

20856297 is a deficient number, since it is larger than the sum of its proper divisors (16966167).

20856297 is a wasteful number, since it uses less digits than its factorization.

20856297 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 198.

The product of its (nonzero) digits is 60480, while the sum is 39.

The square root of 20856297 is about 4566.8694967122. The cubic root of 20856297 is about 275.2616660938.

The spelling of 20856297 in words is "twenty million, eight hundred fifty-six thousand, two hundred ninety-seven".