6518421957 has 4 divisors (see below), whose sum is σ = 8691229280. Its totient is φ = 4345614636.

The previous prime is 6518421953. The next prime is 6518421977. The reversal of 6518421957 is 7591248156.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 6518421957 - 2² = 6518421953 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 (6518421953) 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, 1086403657 + ... + 1086403662.

It is an arithmetic number, because the mean of its divisors is an integer number (2172807320).

Almost surely, 2^6518421957 is an apocalyptic number.

It is an amenable number.

6518421957 is a deficient number, since it is larger than the sum of its proper divisors (2172807323).

6518421957 is a wasteful number, since it uses less digits than its factorization.

6518421957 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2172807322.

The product of its digits is 604800, while the sum is 48.

The square root of 6518421957 is about 80736.7447758454. The cubic root of 6518421957 is about 1868.0169964423.

The spelling of 6518421957 in words is "six billion, five hundred eighteen million, four hundred twenty-one thousand, nine hundred fifty-seven".