20002391 has 4 divisors (see below), whose sum is σ = 20012784. Its totient is φ = 19992000.

The previous prime is 20002369. The next prime is 20002397. The reversal of 20002391 is 19320002.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20002391 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 (20002397) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1370 + ... + 6471.

It is an arithmetic number, because the mean of its divisors is an integer number (5003196).

Almost surely, 2^20002391 is an apocalyptic number.

20002391 is a deficient number, since it is larger than the sum of its proper divisors (10393).

20002391 is an equidigital number, since it uses as much as digits as its factorization.

20002391 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10392.

The product of its (nonzero) digits is 108, while the sum is 17.

The square root of 20002391 is about 4472.4032689372. The cubic root of 20002391 is about 271.4525781827.

Adding to 20002391 its reverse (19320002), we get a palindrome (39322393).

The spelling of 20002391 in words is "twenty million, two thousand, three hundred ninety-one".