6520391 has 4 divisors (see below), whose sum is σ = 6672072. Its totient is φ = 6368712.

The previous prime is 6520387. The next prime is 6520403. The reversal of 6520391 is 1930256.

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

It is a cyclic number.

It is not a de Polignac number, because 6520391 - 2² = 6520387 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 6520391.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6520321) 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, 75776 + ... + 75861.

It is an arithmetic number, because the mean of its divisors is an integer number (1668018).

Almost surely, 2^6520391 is an apocalyptic number.

6520391 is a deficient number, since it is larger than the sum of its proper divisors (151681).

6520391 is a wasteful number, since it uses less digits than its factorization.

6520391 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 151680.

The product of its (nonzero) digits is 1620, while the sum is 26.

The square root of 6520391 is about 2553.5056295219. The cubic root of 6520391 is about 186.8205070361.

The spelling of 6520391 in words is "six million, five hundred twenty thousand, three hundred ninety-one".