720605581 has 2 divisors, whose sum is σ = 720605582. Its totient is φ = 720605580.

The previous prime is 720605579. The next prime is 720605593. The reversal of 720605581 is 185506027.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 688012900 + 32592681 = 26230^2 + 5709^2 .

It is a cyclic number.

It is not a de Polignac number, because 720605581 - 2¹ = 720605579 is a prime.

It is a super-2 number, since 2×720605581² = 1038544806736695122, which contains 22 as substring.

Together with 720605579, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (720600581) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 360302790 + 360302791.

It is an arithmetic number, because the mean of its divisors is an integer number (360302791).

Almost surely, 2^720605581 is an apocalyptic number.

It is an amenable number.

720605581 is a deficient number, since it is larger than the sum of its proper divisors (1).

720605581 is an equidigital number, since it uses as much as digits as its factorization.

720605581 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 16800, while the sum is 34.

The square root of 720605581 is about 26844.0976939066. The cubic root of 720605581 is about 896.5321616321.

The spelling of 720605581 in words is "seven hundred twenty million, six hundred five thousand, five hundred eighty-one".