645857233 has 4 divisors (see below), whose sum is σ = 738122560. Its totient is φ = 553591908.

The previous prime is 645857213. The next prime is 645857249. The reversal of 645857233 is 332758546.

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, and also an emirpimes, since its reverse is a distinct semiprime: 332758546 = 2 ⋅166379273.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-645857233 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 645857233.

It is not an unprimeable number, because it can be changed into a prime (645857213) 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, 46132653 + ... + 46132666.

It is an arithmetic number, because the mean of its divisors is an integer number (184530640).

Almost surely, 2^645857233 is an apocalyptic number.

It is an amenable number.

645857233 is a deficient number, since it is larger than the sum of its proper divisors (92265327).

645857233 is an equidigital number, since it uses as much as digits as its factorization.

645857233 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 92265326.

The product of its digits is 604800, while the sum is 43.

The square root of 645857233 is about 25413.7213528440. The cubic root of 645857233 is about 864.3948602572.

The spelling of 645857233 in words is "six hundred forty-five million, eight hundred fifty-seven thousand, two hundred thirty-three".