645726534 has 8 divisors (see below), whose sum is σ = 1291453080. Its totient is φ = 215242176.

The previous prime is 645726509. The next prime is 645726539. The reversal of 645726534 is 435627546.

It is a sphenic number, since it is the product of 3 distinct primes.

645726534 is an admirable number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (645726539) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 53810539 + ... + 53810550.

It is an arithmetic number, because the mean of its divisors is an integer number (161431635).

Almost surely, 2^645726534 is an apocalyptic number.

645726534 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

645726534 is a wasteful number, since it uses less digits than its factorization.

645726534 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 107621094.

The product of its digits is 604800, while the sum is 42.

The square root of 645726534 is about 25411.1497968903. The cubic root of 645726534 is about 864.3365485233.

The spelling of 645726534 in words is "six hundred forty-five million, seven hundred twenty-six thousand, five hundred thirty-four".