645166840 has 32 divisors (see below), whose sum is σ = 1485388080. Its totient is φ = 252064512.

The previous prime is 645166789. The next prime is 645166849. The reversal of 645166840 is 48661546.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (40).

It is a junction number, because it is equal to n+sod(n) for n = 645166793 and 645166802.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (645166849) 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 7 ways as a sum of consecutive naturals, for example, 185829 + ... + 189268.

Almost surely, 2^645166840 is an apocalyptic number.

It is an amenable number.

645166840 is an abundant number, since it is smaller than the sum of its proper divisors (840221240).

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

645166840 is a wasteful number, since it uses less digits than its factorization.

645166840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 375151 (or 375147 counting only the distinct ones).

The product of its (nonzero) digits is 138240, while the sum is 40.

The square root of 645166840 is about 25400.1346453124. The cubic root of 645166840 is about 864.0867504059.

The spelling of 645166840 in words is "six hundred forty-five million, one hundred sixty-six thousand, eight hundred forty".