645379247 has 4 divisors (see below), whose sum is σ = 645435480. Its totient is φ = 645323016.

The previous prime is 645379243. The next prime is 645379249. The reversal of 645379247 is 742973546.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 645379247 - 2² = 645379243 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 (645379243) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4013 + ... + 36150.

It is an arithmetic number, because the mean of its divisors is an integer number (161358870).

Almost surely, 2^645379247 is an apocalyptic number.

645379247 is a deficient number, since it is larger than the sum of its proper divisors (56233).

645379247 is a wasteful number, since it uses less digits than its factorization.

645379247 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 56232.

The product of its digits is 1270080, while the sum is 47.

The square root of 645379247 is about 25404.3155192184. The cubic root of 645379247 is about 864.1815671906.

The spelling of 645379247 in words is "six hundred forty-five million, three hundred seventy-nine thousand, two hundred forty-seven".