20861916 has 12 divisors (see below), whose sum is σ = 48677832. Its totient is φ = 6953968.

The previous prime is 20861903. The next prime is 20861917. The reversal of 20861916 is 61916802.

It is a tau number, because it is divible by the number of its divisors (12).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20861917) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 869235 + ... + 869258.

It is an arithmetic number, because the mean of its divisors is an integer number (4056486).

Almost surely, 2^20861916 is an apocalyptic number.

It is an amenable number.

20861916 is an abundant number, since it is smaller than the sum of its proper divisors (27815916).

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

20861916 is a wasteful number, since it uses less digits than its factorization.

20861916 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1738500 (or 1738498 counting only the distinct ones).

The product of its (nonzero) digits is 5184, while the sum is 33.

The square root of 20861916 is about 4567.4846469364. The cubic root of 20861916 is about 275.2863837514.

The spelling of 20861916 in words is "twenty million, eight hundred sixty-one thousand, nine hundred sixteen".