65978621 has 8 divisors (see below), whose sum is σ = 69634080. Its totient is φ = 62341488.

The previous prime is 65978617. The next prime is 65978623. The reversal of 65978621 is 12687956.

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 65978621 - 2² = 65978617 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (65978623) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3170 + ... + 11916.

It is an arithmetic number, because the mean of its divisors is an integer number (8704260).

Almost surely, 2^65978621 is an apocalyptic number.

It is an amenable number.

65978621 is a deficient number, since it is larger than the sum of its proper divisors (3655459).

65978621 is a wasteful number, since it uses less digits than its factorization.

65978621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9163.

The product of its digits is 181440, while the sum is 44.

The square root of 65978621 is about 8122.7225115721. The cubic root of 65978621 is about 404.0803621628.

The spelling of 65978621 in words is "sixty-five million, nine hundred seventy-eight thousand, six hundred twenty-one".