65879721 has 12 divisors (see below), whose sum is σ = 97731972. Its totient is φ = 42732576.

The previous prime is 65879717. The next prime is 65879729. The reversal of 65879721 is 12797856.

It can be written as a sum of positive squares in 2 ways, for example, as 39501225 + 26378496 = 6285^2 + 5136^2 .

It is not a de Polignac number, because 65879721 - 2² = 65879717 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (65879729) 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 11 ways as a sum of consecutive naturals, for example, 98586 + ... + 99251.

It is an arithmetic number, because the mean of its divisors is an integer number (8144331).

Almost surely, 2^65879721 is an apocalyptic number.

It is an amenable number.

65879721 is a deficient number, since it is larger than the sum of its proper divisors (31852251).

65879721 is a wasteful number, since it uses less digits than its factorization.

65879721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 197880 (or 197877 counting only the distinct ones).

The product of its digits is 211680, while the sum is 45.

The square root of 65879721 is about 8116.6323681685. The cubic root of 65879721 is about 403.8783596964.

The spelling of 65879721 in words is "sixty-five million, eight hundred seventy-nine thousand, seven hundred twenty-one".