68691891 has 8 divisors (see below), whose sum is σ = 92618640. Its totient is φ = 45279872.

The previous prime is 68691881. The next prime is 68691907. The reversal of 68691891 is 19819686.

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 68691891 - 2⁶ = 68691827 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 68691891.

It is not an unprimeable number, because it can be changed into a prime (68691881) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 128370 + ... + 128903.

It is an arithmetic number, because the mean of its divisors is an integer number (11577330).

Almost surely, 2^68691891 is an apocalyptic number.

68691891 is a deficient number, since it is larger than the sum of its proper divisors (23926749).

68691891 is a wasteful number, since it uses less digits than its factorization.

68691891 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 257365.

The product of its digits is 186624, while the sum is 48.

The square root of 68691891 is about 8288.0571305946. The cubic root of 68691891 is about 409.5451847314.

The spelling of 68691891 in words is "sixty-eight million, six hundred ninety-one thousand, eight hundred ninety-one".