720185981 has 2 divisors, whose sum is σ = 720185982. Its totient is φ = 720185980.

The previous prime is 720185969. The next prime is 720186007. The reversal of 720185981 is 189581027.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 672105625 + 48080356 = 25925^2 + 6934^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-720185981 is a prime.

It is a super-2 number, since 2×720185981² = 1037335694457864722, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (720185281) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 360092990 + 360092991.

It is an arithmetic number, because the mean of its divisors is an integer number (360092991).

Almost surely, 2^720185981 is an apocalyptic number.

It is an amenable number.

720185981 is a deficient number, since it is larger than the sum of its proper divisors (1).

720185981 is an equidigital number, since it uses as much as digits as its factorization.

720185981 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 40320, while the sum is 41.

The square root of 720185981 is about 26836.2810575534. The cubic root of 720185981 is about 896.3581145322.

The spelling of 720185981 in words is "seven hundred twenty million, one hundred eighty-five thousand, nine hundred eighty-one".