645094409 has 4 divisors (see below), whose sum is σ = 673142016. Its totient is φ = 617046804.

The previous prime is 645094391. The next prime is 645094421. The reversal of 645094409 is 904490546.

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-645094409 is a prime.

It is a super-2 number, since 2×645094409² = 832293593046118562, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (645094609) 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, 14023769 + ... + 14023814.

It is an arithmetic number, because the mean of its divisors is an integer number (168285504).

Almost surely, 2^645094409 is an apocalyptic number.

It is an amenable number.

645094409 is a deficient number, since it is larger than the sum of its proper divisors (28047607).

645094409 is a wasteful number, since it uses less digits than its factorization.

645094409 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 28047606.

The product of its (nonzero) digits is 155520, while the sum is 41.

The square root of 645094409 is about 25398.7088057641. The cubic root of 645094409 is about 864.0544130290.

The spelling of 645094409 in words is "six hundred forty-five million, ninety-four thousand, four hundred nine".