668653901 has 4 divisors (see below), whose sum is σ = 671068092. Its totient is φ = 666239712.

The previous prime is 668653897. The next prime is 668653927. The reversal of 668653901 is 109356866.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 43903876 + 624750025 = 6626^2 + 24995^2 .

It is a cyclic number.

It is not a de Polignac number, because 668653901 - 2² = 668653897 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 (668653981) 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, 1206680 + ... + 1207233.

It is an arithmetic number, because the mean of its divisors is an integer number (167767023).

Almost surely, 2^668653901 is an apocalyptic number.

It is an amenable number.

668653901 is a deficient number, since it is larger than the sum of its proper divisors (2414191).

668653901 is a wasteful number, since it uses less digits than its factorization.

668653901 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2414190.

The product of its (nonzero) digits is 233280, while the sum is 44.

The square root of 668653901 is about 25858.3429670194. The cubic root of 668653901 is about 874.4476082437.

The spelling of 668653901 in words is "six hundred sixty-eight million, six hundred fifty-three thousand, nine hundred one".