645852993 has 4 divisors (see below), whose sum is σ = 861137328. Its totient is φ = 430568660.

The previous prime is 645852983. The next prime is 645853003. The reversal of 645852993 is 399258546.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is an interprime number because it is at equal distance from previous prime (645852983) and next prime (645853003).

It is a cyclic number.

It is not a de Polignac number, because 645852993 - 2⁸ = 645852737 is a prime.

It is not an unprimeable number, because it can be changed into a prime (645852953) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 107642163 + ... + 107642168.

It is an arithmetic number, because the mean of its divisors is an integer number (215284332).

Almost surely, 2^645852993 is an apocalyptic number.

It is an amenable number.

645852993 is a deficient number, since it is larger than the sum of its proper divisors (215284335).

645852993 is a wasteful number, since it uses less digits than its factorization.

645852993 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 215284334.

The product of its digits is 2332800, while the sum is 51.

The square root of 645852993 is about 25413.6379332043. The cubic root of 645852993 is about 864.3929686925.

The spelling of 645852993 in words is "six hundred forty-five million, eight hundred fifty-two thousand, nine hundred ninety-three".