20399511 has 12 divisors (see below), whose sum is σ = 29897336. Its totient is φ = 12363120.

The previous prime is 20399503. The next prime is 20399527. The reversal of 20399511 is 11599302.

It is not a de Polignac number, because 20399511 - 2³ = 20399503 is a prime.

It is a super-2 number, since 2×20399511² = 832280098078242, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20399531) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 27736 + ... + 28461.

Almost surely, 2^20399511 is an apocalyptic number.

20399511 is a deficient number, since it is larger than the sum of its proper divisors (9497825).

20399511 is a wasteful number, since it uses less digits than its factorization.

20399511 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 56222 (or 56211 counting only the distinct ones).

The product of its (nonzero) digits is 2430, while the sum is 30.

The square root of 20399511 is about 4516.5817827202. The cubic root of 20399511 is about 273.2372583553.

It can be divided in two parts, 20399 and 511, that added together give a triangular number (20910 = T₂₀₄).

The spelling of 20399511 in words is "twenty million, three hundred ninety-nine thousand, five hundred eleven".