67591991 has 2 divisors, whose sum is σ = 67591992. Its totient is φ = 67591990.

The previous prime is 67591961. The next prime is 67592023. The reversal of 67591991 is 19919576.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 67591991 - 2²⁶ = 483127 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (67591961) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33795995 + 33795996.

It is an arithmetic number, because the mean of its divisors is an integer number (33795996).

Almost surely, 2^67591991 is an apocalyptic number.

67591991 is a deficient number, since it is larger than the sum of its proper divisors (1).

67591991 is an equidigital number, since it uses as much as digits as its factorization.

67591991 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 153090, while the sum is 47.

The square root of 67591991 is about 8221.4348504382. The cubic root of 67591991 is about 407.3475229655.

The spelling of 67591991 in words is "sixty-seven million, five hundred ninety-one thousand, nine hundred ninety-one".