645890787 has 36 divisors (see below), whose sum is σ = 984858840. Its totient is φ = 418356576.

The previous prime is 645890771. The next prime is 645890803. The reversal of 645890787 is 787098546.

It is a powerful number, because all its prime factors have an exponent greater than 1 and also an Achilles number because it is not a perfect power.

It is an interprime number because it is at equal distance from previous prime (645890771) and next prime (645890803).

It is not a de Polignac number, because 645890787 - 2⁴ = 645890771 is a prime.

It is not an unprimeable number, because it can be changed into a prime (645890737) 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 35 ways as a sum of consecutive naturals, for example, 8847783 + ... + 8847855.

It is an arithmetic number, because the mean of its divisors is an integer number (27357190).

Almost surely, 2^645890787 is an apocalyptic number.

645890787 is a gapful number since it is divisible by the number (67) formed by its first and last digit.

645890787 is a deficient number, since it is larger than the sum of its proper divisors (338968053).

645890787 is an frugal number, since it uses more digits than its factorization.

645890787 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 289 (or 143 counting only the distinct ones).

The product of its (nonzero) digits is 3386880, while the sum is 54.

The square root of 645890787 is about 25414.3814994581. The cubic root of 645890787 is about 864.4098292015.

The spelling of 645890787 in words is "six hundred forty-five million, eight hundred ninety thousand, seven hundred eighty-seven".