669427391 has 2 divisors, whose sum is σ = 669427392. Its totient is φ = 669427390.

The previous prime is 669427373. The next prime is 669427403. The reversal of 669427391 is 193724966.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 669427391 - 2⁶ = 669427327 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (669427331) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 334713695 + 334713696.

It is an arithmetic number, because the mean of its divisors is an integer number (334713696).

Almost surely, 2^669427391 is an apocalyptic number.

669427391 is a deficient number, since it is larger than the sum of its proper divisors (1).

669427391 is an equidigital number, since it uses as much as digits as its factorization.

669427391 is an evil number, because the sum of its binary digits is even.

The product of its digits is 489888, while the sum is 47.

The square root of 669427391 is about 25873.2949389907. The cubic root of 669427391 is about 874.7846614583.

The spelling of 669427391 in words is "six hundred sixty-nine million, four hundred twenty-seven thousand, three hundred ninety-one".