65698721 has 4 divisors (see below), whose sum is σ = 71671344. Its totient is φ = 59726100.

The previous prime is 65698697. The next prime is 65698723. The reversal of 65698721 is 12789656.

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 a de Polignac number, because none of the positive numbers 2^k-65698721 is a prime.

It is an alternating number because its digits alternate between even and odd.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (65698723) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2986295 + ... + 2986316.

It is an arithmetic number, because the mean of its divisors is an integer number (17917836).

Almost surely, 2^65698721 is an apocalyptic number.

It is an amenable number.

65698721 is a deficient number, since it is larger than the sum of its proper divisors (5972623).

65698721 is a wasteful number, since it uses less digits than its factorization.

65698721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5972622.

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

The square root of 65698721 is about 8105.4747547568. The cubic root of 65698721 is about 403.5081444418.

The spelling of 65698721 in words is "sixty-five million, six hundred ninety-eight thousand, seven hundred twenty-one".