20856249 has 24 divisors (see below), whose sum is σ = 31941000. Its totient is φ = 13090560.

The previous prime is 20856223. The next prime is 20856259. The reversal of 20856249 is 94265802.

It is a happy number.

20856249 is a `hidden beast` number, since 20 + 8 + 5 + 624 + 9 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 1671849 + 19184400 = 1293^2 + 4380^2 .

It is not a de Polignac number, because 20856249 - 2¹¹ = 20854201 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (20856259) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 9727 + ... + 11675.

It is an arithmetic number, because the mean of its divisors is an integer number (1330875).

Almost surely, 2^20856249 is an apocalyptic number.

20856249 is a gapful number since it is divisible by the number (29) formed by its first and last digit.

It is an amenable number.

20856249 is a deficient number, since it is larger than the sum of its proper divisors (11084751).

20856249 is a wasteful number, since it uses less digits than its factorization.

20856249 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2025 (or 2022 counting only the distinct ones).

The product of its (nonzero) digits is 34560, while the sum is 36.

The square root of 20856249 is about 4566.8642414681. The cubic root of 20856249 is about 275.2614549255.

The spelling of 20856249 in words is "twenty million, eight hundred fifty-six thousand, two hundred forty-nine".