20399161 has 4 divisors (see below), whose sum is σ = 20429712. Its totient is φ = 20368612.

The previous prime is 20399129. The next prime is 20399177. The reversal of 20399161 is 16199302.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 20399161 - 2⁵ = 20399129 is a prime.

It is a super-2 number, since 2×20399161² = 832251539007842, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20399261) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 14251 + ... + 15616.

It is an arithmetic number, because the mean of its divisors is an integer number (5107428).

Almost surely, 2^20399161 is an apocalyptic number.

It is an amenable number.

20399161 is a deficient number, since it is larger than the sum of its proper divisors (30551).

20399161 is an equidigital number, since it uses as much as digits as its factorization.

20399161 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 30550.

The product of its (nonzero) digits is 2916, while the sum is 31.

The square root of 20399161 is about 4516.5430364384. The cubic root of 20399161 is about 273.2356956775.

The spelling of 20399161 in words is "twenty million, three hundred ninety-nine thousand, one hundred sixty-one".