68139745 has 16 divisors (see below), whose sum is σ = 85150800. Its totient is φ = 52300800.

The previous prime is 68139713. The next prime is 68139769. The reversal of 68139745 is 54793186.

It can be written as a sum of positive squares in 8 ways, for example, as 40755456 + 27384289 = 6384^2 + 5233^2 .

It is not a de Polignac number, because 68139745 - 2⁵ = 68139713 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 9781 + ... + 15229.

It is an arithmetic number, because the mean of its divisors is an integer number (5321925).

Almost surely, 2^68139745 is an apocalyptic number.

It is an amenable number.

68139745 is a deficient number, since it is larger than the sum of its proper divisors (17011055).

68139745 is a wasteful number, since it uses less digits than its factorization.

68139745 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5556.

The product of its digits is 181440, while the sum is 43.

The square root of 68139745 is about 8254.6801876269. The cubic root of 68139745 is about 408.4449222535. Note that the first 3 decimals are identical.

The spelling of 68139745 in words is "sixty-eight million, one hundred thirty-nine thousand, seven hundred forty-five".