635997961 has 3 divisors (see below), whose sum is σ = 636023181. Its totient is φ = 635972742.

The previous prime is 635997959. The next prime is 635997979. The reversal of 635997961 is 169799536.

The square root of 635997961 is 25219.

It is a perfect power (a square), and thus also a powerful number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is not a de Polignac number, because 635997961 - 2¹ = 635997959 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (635997941) by changing a digit.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 12610 + ... + 37828.

It is an arithmetic number, because the mean of its divisors is an integer number (212007727).

Almost surely, 2^635997961 is an apocalyptic number.

635997961 is the 25219-th square number.

635997961 is the 12610-th centered octagonal number.

It is an amenable number.

635997961 is a deficient number, since it is larger than the sum of its proper divisors (25220).

635997961 is an frugal number, since it uses more digits than its factorization.

635997961 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 50438 (or 25219 counting only the distinct ones).

The product of its digits is 2755620, while the sum is 55.

The cubic root of 635997961 is about 859.9738413713.

The spelling of 635997961 in words is "six hundred thirty-five million, nine hundred ninety-seven thousand, nine hundred sixty-one".