865720001 has 2 divisors, whose sum is σ = 865720002. Its totient is φ = 865720000.

The previous prime is 865719997. The next prime is 865720003. The reversal of 865720001 is 100027568.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 722319376 + 143400625 = 26876^2 + 11975^2 .

It is a cyclic number.

It is not a de Polignac number, because 865720001 - 2² = 865719997 is a prime.

It is a super-2 number, since 2×865720001² = 1498942240262880002, which contains 22 as substring.

Together with 865720003, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (865720003) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 432860000 + 432860001.

It is an arithmetic number, because the mean of its divisors is an integer number (432860001).

Almost surely, 2^865720001 is an apocalyptic number.

It is an amenable number.

865720001 is a deficient number, since it is larger than the sum of its proper divisors (1).

865720001 is an equidigital number, since it uses as much as digits as its factorization.

865720001 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3360, while the sum is 29.

The square root of 865720001 is about 29423.1201778465. The cubic root of 865720001 is about 953.0722334038.

Adding to 865720001 its reverse (100027568), we get a palindrome (965747569).

The spelling of 865720001 in words is "eight hundred sixty-five million, seven hundred twenty thousand, one".