67908991 has 2 divisors, whose sum is σ = 67908992. Its totient is φ = 67908990.

The previous prime is 67908979. The next prime is 67909001. The reversal of 67908991 is 19980976.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-67908991 is a prime.

It is a super-2 number, since 2×67908991² = 9223262117276162, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (67908961) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33954495 + 33954496.

It is an arithmetic number, because the mean of its divisors is an integer number (33954496).

Almost surely, 2^67908991 is an apocalyptic number.

67908991 is a deficient number, since it is larger than the sum of its proper divisors (1).

67908991 is an equidigital number, since it uses as much as digits as its factorization.

67908991 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 244944, while the sum is 49.

The square root of 67908991 is about 8240.6911724685. The cubic root of 67908991 is about 407.9833370582.

The spelling of 67908991 in words is "sixty-seven million, nine hundred eight thousand, nine hundred ninety-one".