20397599 has 4 divisors (see below), whose sum is σ = 20458464. Its totient is φ = 20336736.

The previous prime is 20397571. The next prime is 20397631. The reversal of 20397599 is 99579302.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20397599 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20397529) 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, 29927 + ... + 30600.

It is an arithmetic number, because the mean of its divisors is an integer number (5114616).

Almost surely, 2^20397599 is an apocalyptic number.

20397599 is a deficient number, since it is larger than the sum of its proper divisors (60865).

20397599 is an equidigital number, since it uses as much as digits as its factorization.

20397599 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 60864.

The product of its (nonzero) digits is 153090, while the sum is 44.

The square root of 20397599 is about 4516.3701132657. The cubic root of 20397599 is about 273.2287214519.

The spelling of 20397599 in words is "twenty million, three hundred ninety-seven thousand, five hundred ninety-nine".