634644376221 has 4 divisors (see below), whose sum is σ = 846192501632. Its totient is φ = 423096250812.

The previous prime is 634644376213. The next prime is 634644376253. The reversal of 634644376221 is 122673446436.

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 not a de Polignac number, because 634644376221 - 2³ = 634644376213 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 (634644376291) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 105774062701 + ... + 105774062706.

It is an arithmetic number, because the mean of its divisors is an integer number (211548125408).

Almost surely, 2^634644376221 is an apocalyptic number.

It is an amenable number.

634644376221 is a deficient number, since it is larger than the sum of its proper divisors (211548125411).

634644376221 is a wasteful number, since it uses less digits than its factorization.

634644376221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 211548125410.

The product of its digits is 3483648, while the sum is 48.

The spelling of 634644376221 in words is "six hundred thirty-four billion, six hundred forty-four million, three hundred seventy-six thousand, two hundred twenty-one".