668212637 has 4 divisors (see below), whose sum is σ = 686272476. Its totient is φ = 650152800.

The previous prime is 668212631. The next prime is 668212639. The reversal of 668212637 is 736212866.

It is a happy number.

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 332187076 + 336025561 = 18226^2 + 18331^2 .

It is a cyclic number.

It is not a de Polignac number, because 668212637 - 2⁸ = 668212381 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 668212594 and 668212603.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (668212631) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 9029864 + ... + 9029937.

It is an arithmetic number, because the mean of its divisors is an integer number (171568119).

Almost surely, 2^668212637 is an apocalyptic number.

It is an amenable number.

668212637 is a deficient number, since it is larger than the sum of its proper divisors (18059839).

668212637 is a wasteful number, since it uses less digits than its factorization.

668212637 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18059838.

The product of its digits is 145152, while the sum is 41.

The square root of 668212637 is about 25849.8092256016. The cubic root of 668212637 is about 874.2552081792.

The spelling of 668212637 in words is "six hundred sixty-eight million, two hundred twelve thousand, six hundred thirty-seven".