645169698 has 40 divisors (see below), whose sum is σ = 1460597292. Its totient is φ = 212834304.

The previous prime is 645169691. The next prime is 645169709. The reversal of 645169698 is 896961546.

It is a happy number.

645169698 is a `hidden beast` number, since 64 + 516 + 9 + 69 + 8 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 602358849 + 42810849 = 24543^2 + 6543^2 .

It is a super-2 number, since 2×645169698² = 832487878434822408, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a Curzon number.

It is a zygodrome in base 3.

It is not an unprimeable number, because it can be changed into a prime (645169691) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 4815 + ... + 36242.

Almost surely, 2^645169698 is an apocalyptic number.

645169698 is an abundant number, since it is smaller than the sum of its proper divisors (815427594).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

645169698 is a wasteful number, since it uses less digits than its factorization.

645169698 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 41168 (or 41159 counting only the distinct ones).

The product of its digits is 2799360, while the sum is 54.

The square root of 645169698 is about 25400.1909047944. The cubic root of 645169698 is about 864.0880263323.

The spelling of 645169698 in words is "six hundred forty-five million, one hundred sixty-nine thousand, six hundred ninety-eight".