20399547 has 16 divisors (see below), whose sum is σ = 31249152. Its totient is φ = 11595360.

The previous prime is 20399537. The next prime is 20399567. The reversal of 20399547 is 74599302.

It is not a de Polignac number, because 20399547 - 2⁴ = 20399531 is a prime.

It is a super-2 number, since 2×20399547² = 832283035610418, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (20399527) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1672 + ... + 6602.

It is an arithmetic number, because the mean of its divisors is an integer number (1953072).

Almost surely, 2^20399547 is an apocalyptic number.

20399547 is a deficient number, since it is larger than the sum of its proper divisors (10849605).

20399547 is a wasteful number, since it uses less digits than its factorization.

20399547 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5138.

The product of its (nonzero) digits is 68040, while the sum is 39.

The square root of 20399547 is about 4516.5857680332. The cubic root of 20399547 is about 273.2374190868.

The spelling of 20399547 in words is "twenty million, three hundred ninety-nine thousand, five hundred forty-seven".