20399311 has 4 divisors (see below), whose sum is σ = 20412000. Its totient is φ = 20386624.

The previous prime is 20399299. The next prime is 20399341. The reversal of 20399311 is 11399302.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 20399311 - 2⁵ = 20399279 is a prime.

It is a super-2 number, since 2×20399311² = 832263778549442, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 20399311.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20399341) 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, 3511 + ... + 7288.

It is an arithmetic number, because the mean of its divisors is an integer number (5103000).

Almost surely, 2^20399311 is an apocalyptic number.

20399311 is a deficient number, since it is larger than the sum of its proper divisors (12689).

20399311 is a wasteful number, since it uses less digits than its factorization.

20399311 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12688.

The product of its (nonzero) digits is 1458, while the sum is 28.

The square root of 20399311 is about 4516.5596420284. The cubic root of 20399311 is about 273.2363653987.

Subtracting from 20399311 its reverse (11399302), we obtain a palindrome (9000009).

The spelling of 20399311 in words is "twenty million, three hundred ninety-nine thousand, three hundred eleven".