20399215 has 8 divisors (see below), whose sum is σ = 24514560. Its totient is φ = 16295712.

The previous prime is 20399213. The next prime is 20399221. The reversal of 20399215 is 51299302.

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

It is a cyclic number.

It is not a de Polignac number, because 20399215 - 2¹ = 20399213 is a prime.

It is a super-2 number, since 2×20399215² = 832255945232450, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20399213) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1426 + ... + 6544.

It is an arithmetic number, because the mean of its divisors is an integer number (3064320).

Almost surely, 2^20399215 is an apocalyptic number.

20399215 is a deficient number, since it is larger than the sum of its proper divisors (4115345).

20399215 is an equidigital number, since it uses as much as digits as its factorization.

20399215 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5921.

The product of its (nonzero) digits is 4860, while the sum is 31.

The square root of 20399215 is about 4516.5490144578. The cubic root of 20399215 is about 273.2359367775.

The spelling of 20399215 in words is "twenty million, three hundred ninety-nine thousand, two hundred fifteen".