20347391 has 4 divisors (see below), whose sum is σ = 20356752. Its totient is φ = 20338032.

The previous prime is 20347361. The next prime is 20347409. The reversal of 20347391 is 19374302.

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-20347391 is a prime.

It is a Duffinian number.

It is a plaindrome in base 16.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20347321) 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, 470 + ... + 6396.

It is an arithmetic number, because the mean of its divisors is an integer number (5089188).

Almost surely, 2^20347391 is an apocalyptic number.

20347391 is a deficient number, since it is larger than the sum of its proper divisors (9361).

20347391 is an equidigital number, since it uses as much as digits as its factorization.

20347391 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9360.

The product of its (nonzero) digits is 4536, while the sum is 29.

The square root of 20347391 is about 4510.8082424328. The cubic root of 20347391 is about 273.0043561766.

The spelling of 20347391 in words is "twenty million, three hundred forty-seven thousand, three hundred ninety-one".