67161991 has 8 divisors (see below), whose sum is σ = 72394560. Its totient is φ = 61938912.

The previous prime is 67161989. The next prime is 67162003. The reversal of 67161991 is 19916176.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 67161991 - 2¹ = 67161989 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (67191991) 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 in 7 ways as a sum of consecutive naturals, for example, 20706 + ... + 23728.

It is an arithmetic number, because the mean of its divisors is an integer number (9049320).

Almost surely, 2^67161991 is an apocalyptic number.

67161991 is a deficient number, since it is larger than the sum of its proper divisors (5232569).

67161991 is a wasteful number, since it uses less digits than its factorization.

67161991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4745.

The product of its digits is 20412, while the sum is 40.

The square root of 67161991 is about 8195.2419732428. The cubic root of 67161991 is about 406.4818770612.

The spelling of 67161991 in words is "sixty-seven million, one hundred sixty-one thousand, nine hundred ninety-one".