20856042 has 40 divisors (see below), whose sum is σ = 49488516. Its totient is φ = 6542208.

The previous prime is 20856041. The next prime is 20856047. The reversal of 20856042 is 24065802.

It can be written as a sum of positive squares in 2 ways, for example, as 15752961 + 5103081 = 3969^2 + 2259^2 .

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a junction number, because it is equal to n+sod(n) for n = 20855997 and 20856015.

It is not an unprimeable number, because it can be changed into a prime (20856041) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 1033 + ... + 6540.

Almost surely, 2^20856042 is an apocalyptic number.

20856042 is an abundant number, since it is smaller than the sum of its proper divisors (28632474).

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

20856042 is a wasteful number, since it uses less digits than its factorization.

20856042 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7604 (or 7595 counting only the distinct ones).

The product of its (nonzero) digits is 3840, while the sum is 27.

The square root of 20856042 is about 4566.8415781588. The cubic root of 20856042 is about 275.2605442582.

The spelling of 20856042 in words is "twenty million, eight hundred fifty-six thousand, forty-two".