20405624 has 8 divisors (see below), whose sum is σ = 38260560. Its totient is φ = 10202808.

The previous prime is 20405579. The next prime is 20405641. The reversal of 20405624 is 42650402.

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

It is a self number, because there is not a number n which added to its sum of digits gives 20405624.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1275344 + ... + 1275359.

It is an arithmetic number, because the mean of its divisors is an integer number (4782570).

Almost surely, 2^20405624 is an apocalyptic number.

It is an amenable number.

20405624 is a deficient number, since it is larger than the sum of its proper divisors (17854936).

20405624 is a wasteful number, since it uses less digits than its factorization.

20405624 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2550709 (or 2550705 counting only the distinct ones).

The product of its (nonzero) digits is 1920, while the sum is 23.

The square root of 20405624 is about 4517.2584606152. The cubic root of 20405624 is about 273.2645487569.

The spelling of 20405624 in words is "twenty million, four hundred five thousand, six hundred twenty-four".