668982997 has 4 divisors (see below), whose sum is σ = 708334956. Its totient is φ = 629631040.

The previous prime is 668982961. The next prime is 668983009. The reversal of 668982997 is 799289866.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 799289866 = 2 ⋅399644933.

It can be written as a sum of positive squares in 2 ways, for example, as 353778481 + 315204516 = 18809^2 + 17754^2 .

It is not a de Polignac number, because 668982997 - 2¹⁵ = 668950229 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 (668982917) 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, 19675954 + ... + 19675987.

It is an arithmetic number, because the mean of its divisors is an integer number (177083739).

Almost surely, 2^668982997 is an apocalyptic number.

It is an amenable number.

668982997 is a deficient number, since it is larger than the sum of its proper divisors (39351959).

668982997 is a wasteful number, since it uses less digits than its factorization.

668982997 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 39351958.

The product of its digits is 23514624, while the sum is 64.

The square root of 668982997 is about 25864.7056236873. The cubic root of 668982997 is about 874.5910456833.

The spelling of 668982997 in words is "six hundred sixty-eight million, nine hundred eighty-two thousand, nine hundred ninety-seven".