645288081 has 8 divisors (see below), whose sum is σ = 866082624. Its totient is φ = 427342800.

The previous prime is 645288079. The next prime is 645288107. The reversal of 645288081 is 180882546.

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

It is not a de Polignac number, because 645288081 - 2¹ = 645288079 is a prime.

It is a super-2 number, since 2×645288081² = 832793414961325122, which contains 22 as substring.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (645288001) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 711786 + ... + 712691.

It is an arithmetic number, because the mean of its divisors is an integer number (108260328).

Almost surely, 2^645288081 is an apocalyptic number.

It is an amenable number.

645288081 is a deficient number, since it is larger than the sum of its proper divisors (220794543).

645288081 is a wasteful number, since it uses less digits than its factorization.

645288081 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1424631.

The product of its (nonzero) digits is 122880, while the sum is 42.

The square root of 645288081 is about 25402.5211544051. The cubic root of 645288081 is about 864.1408739666.

The spelling of 645288081 in words is "six hundred forty-five million, two hundred eighty-eight thousand, eighty-one".