20399205 has 8 divisors (see below), whose sum is σ = 32638752. Its totient is φ = 10879568.

The previous prime is 20399177. The next prime is 20399213. The reversal of 20399205 is 50299302.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20399205 is a prime.

It is a super-2 number, since 2×20399205² = 832255129264050, which contains 22 as substring.

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, 679959 + ... + 679988.

It is an arithmetic number, because the mean of its divisors is an integer number (4079844).

Almost surely, 2^20399205 is an apocalyptic number.

It is an amenable number.

20399205 is a deficient number, since it is larger than the sum of its proper divisors (12239547).

20399205 is a wasteful number, since it uses less digits than its factorization.

20399205 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1359955.

The product of its (nonzero) digits is 4860, while the sum is 30.

The square root of 20399205 is about 4516.5479074178. The cubic root of 20399205 is about 273.2358921294.

The spelling of 20399205 in words is "twenty million, three hundred ninety-nine thousand, two hundred five".