645888887 has 4 divisors (see below), whose sum is σ = 738158736. Its totient is φ = 553619040.

The previous prime is 645888883. The next prime is 645888961. The reversal of 645888887 is 788888546.

It is a happy number.

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 645888887 - 2² = 645888883 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (645888883) 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, 46134914 + ... + 46134927.

It is an arithmetic number, because the mean of its divisors is an integer number (184539684).

Almost surely, 2^645888887 is an apocalyptic number.

645888887 is a deficient number, since it is larger than the sum of its proper divisors (92269849).

645888887 is an equidigital number, since it uses as much as digits as its factorization.

645888887 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 92269848.

The product of its digits is 27525120, while the sum is 62.

The square root of 645888887 is about 25414.3441190207. The cubic root of 645888887 is about 864.4089815968.

The spelling of 645888887 in words is "six hundred forty-five million, eight hundred eighty-eight thousand, eight hundred eighty-seven".