645435751 has 4 divisors (see below), whose sum is σ = 656375400. Its totient is φ = 634496104.

The previous prime is 645435737. The next prime is 645435793. The reversal of 645435751 is 157534546.

645435751 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 is a cyclic number.

It is not a de Polignac number, because 645435751 - 2⁹ = 645435239 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 (645435701) 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, 5469736 + ... + 5469853.

It is an arithmetic number, because the mean of its divisors is an integer number (164093850).

Almost surely, 2^645435751 is an apocalyptic number.

645435751 is a deficient number, since it is larger than the sum of its proper divisors (10939649).

645435751 is a wasteful number, since it uses less digits than its factorization.

645435751 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10939648.

The product of its digits is 252000, while the sum is 40.

The square root of 645435751 is about 25405.4275893951. The cubic root of 645435751 is about 864.2067866206.

The spelling of 645435751 in words is "six hundred forty-five million, four hundred thirty-five thousand, seven hundred fifty-one".