68991385 has 4 divisors (see below), whose sum is σ = 82789668. Its totient is φ = 55193104.

The previous prime is 68991361. The next prime is 68991407. The reversal of 68991385 is 58319986.

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 26337424 + 42653961 = 5132^2 + 6531^2 .

It is a cyclic number.

It is not a de Polignac number, because 68991385 - 2⁷ = 68991257 is a prime.

It is a super-2 number, since 2×68991385² = 9519622408436450, which contains 22 as substring.

It is a Smith number, since the sum of its digits (49) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6899134 + ... + 6899143.

It is an arithmetic number, because the mean of its divisors is an integer number (20697417).

Almost surely, 2^68991385 is an apocalyptic number.

It is an amenable number.

68991385 is a deficient number, since it is larger than the sum of its proper divisors (13798283).

68991385 is a wasteful number, since it uses less digits than its factorization.

68991385 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13798282.

The product of its digits is 466560, while the sum is 49.

The square root of 68991385 is about 8306.1052846686. The cubic root of 68991385 is about 410.1395222160.

The spelling of 68991385 in words is "sixty-eight million, nine hundred ninety-one thousand, three hundred eighty-five".