646634623 has 4 divisors (see below), whose sum is σ = 653037048. Its totient is φ = 640232200.

The previous prime is 646634579. The next prime is 646634641. The reversal of 646634623 is 326436646.

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 646634623 - 2¹⁷ = 646503551 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 (646634683) 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, 3201061 + ... + 3201262.

It is an arithmetic number, because the mean of its divisors is an integer number (163259262).

Almost surely, 2^646634623 is an apocalyptic number.

646634623 is a deficient number, since it is larger than the sum of its proper divisors (6402425).

646634623 is a wasteful number, since it uses less digits than its factorization.

646634623 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6402424.

The product of its digits is 373248, while the sum is 40.

The square root of 646634623 is about 25429.0114436248. The cubic root of 646634623 is about 864.7415325859.

The spelling of 646634623 in words is "six hundred forty-six million, six hundred thirty-four thousand, six hundred twenty-three".