645691022 has 8 divisors (see below), whose sum is σ = 1019512200. Its totient is φ = 305853624.

The previous prime is 645691021. The next prime is 645691031. The reversal of 645691022 is 220196546.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (645691021) 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, 8495897 + ... + 8495972.

It is an arithmetic number, because the mean of its divisors is an integer number (127439025).

Almost surely, 2^645691022 is an apocalyptic number.

645691022 is a deficient number, since it is larger than the sum of its proper divisors (373821178).

645691022 is a wasteful number, since it uses less digits than its factorization.

645691022 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16991890.

The product of its (nonzero) digits is 25920, while the sum is 35.

The square root of 645691022 is about 25410.4510388934. The cubic root of 645691022 is about 864.3207033831.

The spelling of 645691022 in words is "six hundred forty-five million, six hundred ninety-one thousand, twenty-two".