68061991 has 8 divisors (see below), whose sum is σ = 72673920. Its totient is φ = 63587832.

The previous prime is 68061989. The next prime is 68062013. The reversal of 68061991 is 19916086.

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 68061991 - 2¹ = 68061989 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 (68061901) 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, 33421 + ... + 35398.

It is an arithmetic number, because the mean of its divisors is an integer number (9084240).

Almost surely, 2^68061991 is an apocalyptic number.

68061991 is a deficient number, since it is larger than the sum of its proper divisors (4611929).

68061991 is a wasteful number, since it uses less digits than its factorization.

68061991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 68885.

The product of its (nonzero) digits is 23328, while the sum is 40.

The square root of 68061991 is about 8249.9691514575. The cubic root of 68061991 is about 408.2895048150.

The spelling of 68061991 in words is "sixty-eight million, sixty-one thousand, nine hundred ninety-one".