20405630 has 16 divisors (see below), whose sum is σ = 41977440. Its totient is φ = 6996192.

The previous prime is 20405579. The next prime is 20405641. The reversal of 20405630 is 3650402.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 145685 + ... + 145824.

It is an arithmetic number, because the mean of its divisors is an integer number (2623590).

Almost surely, 2^20405630 is an apocalyptic number.

20405630 is an abundant number, since it is smaller than the sum of its proper divisors (21571810).

20405630 is a wasteful number, since it uses less digits than its factorization.

20405630 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 291523.

The product of its (nonzero) digits is 720, while the sum is 20.

The square root of 20405630 is about 4517.2591247348. The cubic root of 20405630 is about 273.2645755402.

The spelling of 20405630 in words is "twenty million, four hundred five thousand, six hundred thirty".