20904861 has 8 divisors (see below), whose sum is σ = 29085120. Its totient is φ = 13330592.

The previous prime is 20904859. The next prime is 20904899. The reversal of 20904861 is 16840902.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 20904861 - 2¹ = 20904859 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20904811) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 151416 + ... + 151553.

It is an arithmetic number, because the mean of its divisors is an integer number (3635640).

Almost surely, 2^20904861 is an apocalyptic number.

It is an amenable number.

20904861 is a deficient number, since it is larger than the sum of its proper divisors (8180259).

20904861 is a wasteful number, since it uses less digits than its factorization.

20904861 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 302995.

The product of its (nonzero) digits is 3456, while the sum is 30.

The square root of 20904861 is about 4572.1833952719. The cubic root of 20904861 is about 275.4751499046.

The spelling of 20904861 in words is "twenty million, nine hundred four thousand, eight hundred sixty-one".