20904623 has 4 divisors (see below), whose sum is σ = 20916720. Its totient is φ = 20892528.

The previous prime is 20904619. The next prime is 20904641. The reversal of 20904623 is 32640902.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 20904623 - 2² = 20904619 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20904592 and 20904601.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20904643) 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, 2915 + ... + 7092.

It is an arithmetic number, because the mean of its divisors is an integer number (5229180).

Almost surely, 2^20904623 is an apocalyptic number.

20904623 is a deficient number, since it is larger than the sum of its proper divisors (12097).

20904623 is a wasteful number, since it uses less digits than its factorization.

20904623 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12096.

The product of its (nonzero) digits is 2592, while the sum is 26.

The square root of 20904623 is about 4572.1573682453. The cubic root of 20904623 is about 275.4741044805.

The spelling of 20904623 in words is "twenty million, nine hundred four thousand, six hundred twenty-three".