68499721 has 4 divisors (see below), whose sum is σ = 68537092. Its totient is φ = 68462352.

The previous prime is 68499719. The next prime is 68499757. The reversal of 68499721 is 12799486.

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

It can be written as a sum of positive squares in 2 ways, for example, as 55279225 + 13220496 = 7435^2 + 3636^2 .

It is a cyclic number.

It is not a de Polignac number, because 68499721 - 2¹ = 68499719 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (68499701) 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, 15786 + ... + 19651.

It is an arithmetic number, because the mean of its divisors is an integer number (17134273).

Almost surely, 2^68499721 is an apocalyptic number.

It is an amenable number.

68499721 is a deficient number, since it is larger than the sum of its proper divisors (37371).

68499721 is a wasteful number, since it uses less digits than its factorization.

68499721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 37370.

The product of its digits is 217728, while the sum is 46.

The square root of 68499721 is about 8276.4558235999. The cubic root of 68499721 is about 409.1629183393.

The spelling of 68499721 in words is "sixty-eight million, four hundred ninety-nine thousand, seven hundred twenty-one".