645268729 has 4 divisors (see below), whose sum is σ = 737449984. Its totient is φ = 553087476.

The previous prime is 645268727. The next prime is 645268733. The reversal of 645268729 is 927862546.

645268729 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, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 645268729 - 2¹ = 645268727 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (645268727) 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, 46090617 + ... + 46090630.

It is an arithmetic number, because the mean of its divisors is an integer number (184362496).

Almost surely, 2^645268729 is an apocalyptic number.

It is an amenable number.

645268729 is a deficient number, since it is larger than the sum of its proper divisors (92181255).

645268729 is an equidigital number, since it uses as much as digits as its factorization.

645268729 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 92181254.

The product of its digits is 1451520, while the sum is 49.

The square root of 645268729 is about 25402.1402444755. The cubic root of 645268729 is about 864.1322354366.

The spelling of 645268729 in words is "six hundred forty-five million, two hundred sixty-eight thousand, seven hundred twenty-nine".