20431605 has 32 divisors (see below), whose sum is σ = 33928704. Its totient is φ = 10492416.

The previous prime is 20431591. The next prime is 20431627. The reversal of 20431605 is 50613402.

It is a happy number.

It is not a de Polignac number, because 20431605 - 2¹¹ = 20429557 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 51267 + ... + 51663.

It is an arithmetic number, because the mean of its divisors is an integer number (1060272).

Almost surely, 2^20431605 is an apocalyptic number.

It is an amenable number.

20431605 is a deficient number, since it is larger than the sum of its proper divisors (13497099).

20431605 is a wasteful number, since it uses less digits than its factorization.

20431605 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 525.

The product of its (nonzero) digits is 720, while the sum is 21.

The square root of 20431605 is about 4520.1332944948. The cubic root of 20431605 is about 273.3804755426.

The spelling of 20431605 in words is "twenty million, four hundred thirty-one thousand, six hundred five".