20345399 has 4 divisors (see below), whose sum is σ = 20387664. Its totient is φ = 20303136.

The previous prime is 20345359. The next prime is 20345411. The reversal of 20345399 is 99354302.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 99354302 = 2 ⋅49677151.

It is a cyclic number.

It is not a de Polignac number, because 20345399 - 2¹² = 20341303 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 (20345359) 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, 20402 + ... + 21375.

It is an arithmetic number, because the mean of its divisors is an integer number (5096916).

Almost surely, 2^20345399 is an apocalyptic number.

20345399 is a deficient number, since it is larger than the sum of its proper divisors (42265).

20345399 is an equidigital number, since it uses as much as digits as its factorization.

20345399 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 42264.

The product of its (nonzero) digits is 29160, while the sum is 35.

The square root of 20345399 is about 4510.5874340267. The cubic root of 20345399 is about 272.9954468865.

The spelling of 20345399 in words is "twenty million, three hundred forty-five thousand, three hundred ninety-nine".