668867851 has 2 divisors, whose sum is σ = 668867852. Its totient is φ = 668867850.

The previous prime is 668867821. The next prime is 668867869. The reversal of 668867851 is 158768866.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 668867851 - 2⁵ = 668867819 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 668867792 and 668867801.

It is not a weakly prime, because it can be changed into another prime (668867821) 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 as a sum of consecutive naturals, namely, 334433925 + 334433926.

It is an arithmetic number, because the mean of its divisors is an integer number (334433926).

Almost surely, 2^668867851 is an apocalyptic number.

668867851 is a deficient number, since it is larger than the sum of its proper divisors (1).

668867851 is an equidigital number, since it uses as much as digits as its factorization.

668867851 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3870720, while the sum is 55.

The square root of 668867851 is about 25862.4795988320. The cubic root of 668867851 is about 874.5408643188.

The spelling of 668867851 in words is "six hundred sixty-eight million, eight hundred sixty-seven thousand, eight hundred fifty-one".