68445721 has 8 divisors (see below), whose sum is σ = 69888384. Its totient is φ = 67013520.

The previous prime is 68445703. The next prime is 68445731. The reversal of 68445721 is 12754486.

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 68445721 - 2²³ = 60057113 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (68445731) 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, 11376 + ... + 16318.

It is an arithmetic number, because the mean of its divisors is an integer number (8736048).

Almost surely, 2^68445721 is an apocalyptic number.

68445721 is a gapful number since it is divisible by the number (61) formed by its first and last digit.

It is an amenable number.

68445721 is a deficient number, since it is larger than the sum of its proper divisors (1442663).

68445721 is a wasteful number, since it uses less digits than its factorization.

68445721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5231.

The product of its digits is 53760, while the sum is 37.

The square root of 68445721 is about 8273.1929144678. The cubic root of 68445721 is about 409.0553723729.

The spelling of 68445721 in words is "sixty-eight million, four hundred forty-five thousand, seven hundred twenty-one".