20851236 has 48 divisors (see below), whose sum is σ = 61783680. Its totient is φ = 5957280.

The previous prime is 20851223. The next prime is 20851253. The reversal of 20851236 is 63215802.

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

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 13035 + ... + 14546.

It is an arithmetic number, because the mean of its divisors is an integer number (1287160).

Almost surely, 2^20851236 is an apocalyptic number.

It is an amenable number.

20851236 is an abundant number, since it is smaller than the sum of its proper divisors (40932444).

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

20851236 is a wasteful number, since it uses less digits than its factorization.

20851236 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27601 (or 27593 counting only the distinct ones).

The product of its (nonzero) digits is 2880, while the sum is 27.

The square root of 20851236 is about 4566.3153636165. The cubic root of 20851236 is about 275.2393992458.

Subtracting from 20851236 its product of nonzero digits (2880), we obtain a square (20848356 = 4566²).

It can be divided in two parts, 2085 and 1236, that added together give a triangular number (3321 = T₈₁).

The spelling of 20851236 in words is "twenty million, eight hundred fifty-one thousand, two hundred thirty-six".