787981 has 2 divisors, whose sum is σ = 787982. Its totient is φ = 787980.

The previous prime is 787973. The next prime is 787993. The reversal of 787981 is 189787.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 749956 + 38025 = 866^2 + 195^2 .

It is a cyclic number.

It is not a de Polignac number, because 787981 - 2³ = 787973 is a prime.

It is a super-2 number, since 2×787981² = 1241828112722, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (787181) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 393990 + 393991.

It is an arithmetic number, because the mean of its divisors is an integer number (393991).

2⁷⁸⁷⁹⁸¹ is an apocalyptic number.

It is an amenable number.

787981 is a deficient number, since it is larger than the sum of its proper divisors (1).

787981 is an equidigital number, since it uses as much as digits as its factorization.

787981 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 28224, while the sum is 40.

The square root of 787981 is about 887.6829388920. The cubic root of 787981 is about 92.3645350925.

The spelling of 787981 in words is "seven hundred eighty-seven thousand, nine hundred eighty-one".