68591721 has 8 divisors (see below), whose sum is σ = 99769824. Its totient is φ = 41570720.

The previous prime is 68591701. The next prime is 68591737. The reversal of 68591721 is 12719586.

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 68591721 - 2¹¹ = 68589673 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 68591721.

It is not an unprimeable number, because it can be changed into a prime (68591701) 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, 1039236 + ... + 1039301.

It is an arithmetic number, because the mean of its divisors is an integer number (12471228).

Almost surely, 2^68591721 is an apocalyptic number.

It is an amenable number.

68591721 is a deficient number, since it is larger than the sum of its proper divisors (31178103).

68591721 is a wasteful number, since it uses less digits than its factorization.

68591721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2078551.

The product of its digits is 30240, while the sum is 39.

The square root of 68591721 is about 8282.0118932540. The cubic root of 68591721 is about 409.3460146989.

The spelling of 68591721 in words is "sixty-eight million, five hundred ninety-one thousand, seven hundred twenty-one".