645733397 has 4 divisors (see below), whose sum is σ = 657917100. Its totient is φ = 633549696.

The previous prime is 645733351. The next prime is 645733447. The reversal of 645733397 is 793337546.

645733397 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 244171876 + 401561521 = 15626^2 + 20039^2 .

It is a cyclic number.

It is not a de Polignac number, because 645733397 - 2¹⁴ = 645717013 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (645733997) 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, 6091772 + ... + 6091877.

It is an arithmetic number, because the mean of its divisors is an integer number (164479275).

Almost surely, 2^645733397 is an apocalyptic number.

It is an amenable number.

645733397 is a deficient number, since it is larger than the sum of its proper divisors (12183703).

645733397 is a wasteful number, since it uses less digits than its factorization.

645733397 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12183702.

The product of its digits is 1428840, while the sum is 47.

The square root of 645733397 is about 25411.2848356788. The cubic root of 645733397 is about 864.3396106661.

The spelling of 645733397 in words is "six hundred forty-five million, seven hundred thirty-three thousand, three hundred ninety-seven".