349787981 has 2 divisors, whose sum is σ = 349787982. Its totient is φ = 349787980.

The previous prime is 349787941. The next prime is 349787983. The reversal of 349787981 is 189787943.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 346332100 + 3455881 = 18610^2 + 1859^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-349787981 is a prime.

It is a super-2 number, since 2×349787981² = 244703263304112722, which contains 22 as substring.

It is a Sophie Germain prime.

Together with 349787983, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (349787983) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 174893990 + 174893991.

It is an arithmetic number, because the mean of its divisors is an integer number (174893991).

Almost surely, 2^349787981 is an apocalyptic number.

It is an amenable number.

349787981 is a deficient number, since it is larger than the sum of its proper divisors (1).

349787981 is an equidigital number, since it uses as much as digits as its factorization.

349787981 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3048192, while the sum is 56.

The square root of 349787981 is about 18702.6196293460. The cubic root of 349787981 is about 704.5875433935.

The spelling of 349787981 in words is "three hundred forty-nine million, seven hundred eighty-seven thousand, nine hundred eighty-one".