645411191 has 4 divisors (see below), whose sum is σ = 659143392. Its totient is φ = 631678992.

The previous prime is 645411187. The next prime is 645411199. The reversal of 645411191 is 191114546.

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 645411191 - 2² = 645411187 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 (645411199) 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, 6866030 + ... + 6866123.

It is an arithmetic number, because the mean of its divisors is an integer number (164785848).

Almost surely, 2^645411191 is an apocalyptic number.

645411191 is a deficient number, since it is larger than the sum of its proper divisors (13732201).

645411191 is a wasteful number, since it uses less digits than its factorization.

645411191 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13732200.

The product of its digits is 4320, while the sum is 32.

The square root of 645411191 is about 25404.9442235168. The cubic root of 645411191 is about 864.1958249368.

The spelling of 645411191 in words is "six hundred forty-five million, four hundred eleven thousand, one hundred ninety-one".