68640515 has 8 divisors (see below), whose sum is σ = 82739328. Its totient is φ = 54665280.

The previous prime is 68640511. The next prime is 68640529. The reversal of 68640515 is 51504686.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 68640515 - 2² = 68640511 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (68640511) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 29666 + ... + 31895.

It is an arithmetic number, because the mean of its divisors is an integer number (10342416).

Almost surely, 2^68640515 is an apocalyptic number.

68640515 is a deficient number, since it is larger than the sum of its proper divisors (14098813).

68640515 is a wasteful number, since it uses less digits than its factorization.

68640515 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 61789.

The product of its (nonzero) digits is 28800, while the sum is 35.

The square root of 68640515 is about 8284.9571513678. The cubic root of 68640515 is about 409.4430569990.

The spelling of 68640515 in words is "sixty-eight million, six hundred forty thousand, five hundred fifteen".