68399521 has 8 divisors (see below), whose sum is σ = 71392104. Its totient is φ = 65470080.

The previous prime is 68399503. The next prime is 68399531. The reversal of 68399521 is 12599386.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 6305121 + 62094400 = 2511^2 + 7880^2 .

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 68399521 - 2⁵ = 68399489 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (68399501) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 13566 + ... + 17911.

It is an arithmetic number, because the mean of its divisors is an integer number (8924013).

Almost surely, 2^68399521 is an apocalyptic number.

It is an amenable number.

68399521 is a deficient number, since it is larger than the sum of its proper divisors (2992583).

68399521 is a wasteful number, since it uses less digits than its factorization.

68399521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 31571.

The product of its digits is 116640, while the sum is 43.

The square root of 68399521 is about 8270.4002926098. The cubic root of 68399521 is about 408.9633159152.

The spelling of 68399521 in words is "sixty-eight million, three hundred ninety-nine thousand, five hundred twenty-one".