634656621 has 4 divisors (see below), whose sum is σ = 846208832. Its totient is φ = 423104412.

The previous prime is 634656599. The next prime is 634656647. The reversal of 634656621 is 126656436.

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 634656621 - 2¹⁵ = 634623853 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 634656621.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (634652621) 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, 105776101 + ... + 105776106.

It is an arithmetic number, because the mean of its divisors is an integer number (211552208).

Almost surely, 2^634656621 is an apocalyptic number.

It is an amenable number.

634656621 is a deficient number, since it is larger than the sum of its proper divisors (211552211).

634656621 is a wasteful number, since it uses less digits than its factorization.

634656621 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 211552210.

The product of its digits is 155520, while the sum is 39.

The square root of 634656621 is about 25192.3921254017. The cubic root of 634656621 is about 859.3688450927.

The spelling of 634656621 in words is "six hundred thirty-four million, six hundred fifty-six thousand, six hundred twenty-one".