669126691 has 2 divisors, whose sum is σ = 669126692. Its totient is φ = 669126690.

The previous prime is 669126677. The next prime is 669126697. The reversal of 669126691 is 196621966.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-669126691 is a prime.

It is not a weakly prime, because it can be changed into another prime (669126697) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 334563345 + 334563346.

It is an arithmetic number, because the mean of its divisors is an integer number (334563346).

Almost surely, 2^669126691 is an apocalyptic number.

669126691 is a deficient number, since it is larger than the sum of its proper divisors (1).

669126691 is an equidigital number, since it uses as much as digits as its factorization.

669126691 is an evil number, because the sum of its binary digits is even.

The product of its digits is 209952, while the sum is 46.

The square root of 669126691 is about 25867.4832753401. The cubic root of 669126691 is about 874.6536603733.

The spelling of 669126691 in words is "six hundred sixty-nine million, one hundred twenty-six thousand, six hundred ninety-one".