6645843397 has 4 divisors (see below), whose sum is σ = 6693655360. Its totient is φ = 6598031436.

The previous prime is 6645843359. The next prime is 6645843401. The reversal of 6645843397 is 7933485466.

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 a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-6645843397 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 (6645873397) 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, 23905773 + ... + 23906050.

It is an arithmetic number, because the mean of its divisors is an integer number (1673413840).

Almost surely, 2^6645843397 is an apocalyptic number.

It is an amenable number.

6645843397 is a deficient number, since it is larger than the sum of its proper divisors (47811963).

6645843397 is a wasteful number, since it uses less digits than its factorization.

6645843397 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 47811962.

The product of its digits is 13063680, while the sum is 55.

The square root of 6645843397 is about 81522.0423995866. The cubic root of 6645843397 is about 1880.1104693084.

The spelling of 6645843397 in words is "six billion, six hundred forty-five million, eight hundred forty-three thousand, three hundred ninety-seven".