20609990 has 16 divisors (see below), whose sum is σ = 37346400. Its totient is φ = 8188800.

The previous prime is 20609983. The next prime is 20610013. The reversal of 20609990 is 9990602.

It is a self number, because there is not a number n which added to its sum of digits gives 20609990.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5315 + ... + 8334.

It is an arithmetic number, because the mean of its divisors is an integer number (2334150).

Almost surely, 2^20609990 is an apocalyptic number.

20609990 is a deficient number, since it is larger than the sum of its proper divisors (16736410).

20609990 is a wasteful number, since it uses less digits than its factorization.

20609990 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13807.

The product of its (nonzero) digits is 8748, while the sum is 35.

The square root of 20609990 is about 4539.8226837620. The cubic root of 20609990 is about 274.1737846513.

The spelling of 20609990 in words is "twenty million, six hundred nine thousand, nine hundred ninety".