646607725638 has 32 divisors (see below), whose sum is σ = 1478031611904. Its totient is φ = 184736177472.

The previous prime is 646607725637. The next prime is 646607725663. The reversal of 646607725638 is 836527706646.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (646607725633) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 539506 + ... + 1258682.

It is an arithmetic number, because the mean of its divisors is an integer number (46188487872).

Almost surely, 2^646607725638 is an apocalyptic number.

646607725638 is an abundant number, since it is smaller than the sum of its proper divisors (831423886266).

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

646607725638 is a wasteful number, since it uses less digits than its factorization.

646607725638 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 740596.

The product of its (nonzero) digits is 60963840, while the sum is 60.

The spelling of 646607725638 in words is "six hundred forty-six billion, six hundred seven million, seven hundred twenty-five thousand, six hundred thirty-eight".