68135491 has 4 divisors (see below), whose sum is σ = 68428152. Its totient is φ = 67842832.

The previous prime is 68135479. The next prime is 68135503. The reversal of 68135491 is 19453186.

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

It is an interprime number because it is at equal distance from previous prime (68135479) and next prime (68135503).

It is a cyclic number.

It is not a de Polignac number, because 68135491 - 2²⁵ = 34581059 is a prime.

It is a super-2 number, since 2×68135491² = 9284890267622162, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 68135491.

It is not an unprimeable number, because it can be changed into a prime (68135401) 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, 145981 + ... + 146446.

It is an arithmetic number, because the mean of its divisors is an integer number (17107038).

Almost surely, 2^68135491 is an apocalyptic number.

68135491 is a deficient number, since it is larger than the sum of its proper divisors (292661).

68135491 is a wasteful number, since it uses less digits than its factorization.

68135491 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 292660.

The product of its digits is 25920, while the sum is 37.

The square root of 68135491 is about 8254.4225115995. The cubic root of 68135491 is about 408.4364222664.

The spelling of 68135491 in words is "sixty-eight million, one hundred thirty-five thousand, four hundred ninety-one".