67399991 has 2 divisors, whose sum is σ = 67399992. Its totient is φ = 67399990.

The previous prime is 67399979. The next prime is 67399993. The reversal of 67399991 is 19999376.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 67399991 - 2²² = 63205687 is a prime.

It is a Sophie Germain prime.

Together with 67399993, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (67399993) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33699995 + 33699996.

It is an arithmetic number, because the mean of its divisors is an integer number (33699996).

Almost surely, 2^67399991 is an apocalyptic number.

67399991 is a deficient number, since it is larger than the sum of its proper divisors (1).

67399991 is an equidigital number, since it uses as much as digits as its factorization.

67399991 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 826686, while the sum is 53.

The square root of 67399991 is about 8209.7497525808. The cubic root of 67399991 is about 406.9614570290.

The spelling of 67399991 in words is "sixty-seven million, three hundred ninety-nine thousand, nine hundred ninety-one".