645552291 has 4 divisors (see below), whose sum is σ = 860736392. Its totient is φ = 430368192.

The previous prime is 645552269. The next prime is 645552301. The reversal of 645552291 is 192255546.

645552291 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 645552291 - 2¹⁰ = 645551267 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (645552211) 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, 107592046 + ... + 107592051.

It is an arithmetic number, because the mean of its divisors is an integer number (215184098).

Almost surely, 2^645552291 is an apocalyptic number.

645552291 is a deficient number, since it is larger than the sum of its proper divisors (215184101).

645552291 is a wasteful number, since it uses less digits than its factorization.

645552291 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 215184100.

The product of its digits is 108000, while the sum is 39.

The square root of 645552291 is about 25407.7210902513. The cubic root of 645552291 is about 864.2587972701.

The spelling of 645552291 in words is "six hundred forty-five million, five hundred fifty-two thousand, two hundred ninety-one".