67991147 has 4 divisors (see below), whose sum is σ = 77704176. Its totient is φ = 58278120.

The previous prime is 67991141. The next prime is 67991159. The reversal of 67991147 is 74119976.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-67991147 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 67991098 and 67991107.

It is not an unprimeable number, because it can be changed into a prime (67991141) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4856504 + ... + 4856517.

It is an arithmetic number, because the mean of its divisors is an integer number (19426044).

Almost surely, 2^67991147 is an apocalyptic number.

67991147 is a deficient number, since it is larger than the sum of its proper divisors (9713029).

67991147 is an equidigital number, since it uses as much as digits as its factorization.

67991147 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9713028.

The product of its digits is 95256, while the sum is 44.

The square root of 67991147 is about 8245.6744417907. The cubic root of 67991147 is about 408.1477962403.

The spelling of 67991147 in words is "sixty-seven million, nine hundred ninety-one thousand, one hundred forty-seven".