634705921 has 2 divisors, whose sum is σ = 634705922. Its totient is φ = 634705920.

The previous prime is 634705901. The next prime is 634705927. The reversal of 634705921 is 129507436.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 632019600 + 2686321 = 25140^2 + 1639^2 .

It is a cyclic number.

It is not a de Polignac number, because 634705921 - 2²³ = 626317313 is a prime.

It is not a weakly prime, because it can be changed into another prime (634705927) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 317352960 + 317352961.

It is an arithmetic number, because the mean of its divisors is an integer number (317352961).

Almost surely, 2^634705921 is an apocalyptic number.

It is an amenable number.

634705921 is a deficient number, since it is larger than the sum of its proper divisors (1).

634705921 is an equidigital number, since it uses as much as digits as its factorization.

634705921 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 45360, while the sum is 37.

The square root of 634705921 is about 25193.3705764036. The cubic root of 634705921 is about 859.3910963835.

The spelling of 634705921 in words is "six hundred thirty-four million, seven hundred five thousand, nine hundred twenty-one".