645384397 has 4 divisors (see below), whose sum is σ = 737582176. Its totient is φ = 553186620.

The previous prime is 645384371. The next prime is 645384407. The reversal of 645384397 is 793483546.

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 645384397 - 2⁷ = 645384269 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 645384397.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (645384317) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 46098879 + ... + 46098892.

It is an arithmetic number, because the mean of its divisors is an integer number (184395544).

Almost surely, 2^645384397 is an apocalyptic number.

It is an amenable number.

645384397 is a deficient number, since it is larger than the sum of its proper divisors (92197779).

645384397 is an equidigital number, since it uses as much as digits as its factorization.

645384397 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 92197778.

The product of its digits is 2177280, while the sum is 49.

The square root of 645384397 is about 25404.4168797475. The cubic root of 645384397 is about 864.1838658510.

The spelling of 645384397 in words is "six hundred forty-five million, three hundred eighty-four thousand, three hundred ninety-seven".