20856872 has 8 divisors (see below), whose sum is σ = 39106650. Its totient is φ = 10428432.

The previous prime is 20856839. The next prime is 20856877. The reversal of 20856872 is 27865802.

It can be written as a sum of positive squares in only one way, i.e., 17522596 + 3334276 = 4186^2 + 1826^2 .

It is a tau number, because it is divible by the number of its divisors (8).

It is not an unprimeable number, because it can be changed into a prime (20856877) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1303547 + ... + 1303562.

Almost surely, 2^20856872 is an apocalyptic number.

It is an amenable number.

20856872 is a deficient number, since it is larger than the sum of its proper divisors (18249778).

20856872 is a wasteful number, since it uses less digits than its factorization.

20856872 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2607115 (or 2607111 counting only the distinct ones).

The product of its (nonzero) digits is 53760, while the sum is 38.

The square root of 20856872 is about 4566.9324496866. The cubic root of 20856872 is about 275.2641956896.

The spelling of 20856872 in words is "twenty million, eight hundred fifty-six thousand, eight hundred seventy-two".