65978689 has 4 divisors (see below), whose sum is σ = 75404224. Its totient is φ = 56553156.

The previous prime is 65978669. The next prime is 65978701. The reversal of 65978689 is 98687956.

65978689 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 65978689 - 2⁵ = 65978657 is a prime.

It is not an unprimeable number, because it can be changed into a prime (65978639) 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 3 ways as a sum of consecutive naturals, for example, 4712757 + ... + 4712770.

It is an arithmetic number, because the mean of its divisors is an integer number (18851056).

Almost surely, 2^65978689 is an apocalyptic number.

It is an amenable number.

65978689 is a deficient number, since it is larger than the sum of its proper divisors (9425535).

65978689 is an equidigital number, since it uses as much as digits as its factorization.

65978689 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9425534.

The product of its digits is 6531840, while the sum is 58.

The square root of 65978689 is about 8122.7266973597. The cubic root of 65978689 is about 404.0805009828.

The spelling of 65978689 in words is "sixty-five million, nine hundred seventy-eight thousand, six hundred eighty-nine".