447787981 has 2 divisors, whose sum is σ = 447787982. Its totient is φ = 447787980.

The previous prime is 447787979. The next prime is 447788017. The reversal of 447787981 is 189787744.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 251507881 + 196280100 = 15859^2 + 14010^2 .

It is a cyclic number.

It is not a de Polignac number, because 447787981 - 2¹ = 447787979 is a prime.

It is a super-2 number, since 2×447787981² = 401028151856112722, which contains 22 as substring.

Together with 447787979, 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 (447787961) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 223893990 + 223893991.

It is an arithmetic number, because the mean of its divisors is an integer number (223893991).

Almost surely, 2^447787981 is an apocalyptic number.

It is an amenable number.

447787981 is a deficient number, since it is larger than the sum of its proper divisors (1).

447787981 is an equidigital number, since it uses as much as digits as its factorization.

447787981 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3161088, while the sum is 55.

The square root of 447787981 is about 21161.0014177023. The cubic root of 447787981 is about 765.0517463964.

The spelling of 447787981 in words is "four hundred forty-seven million, seven hundred eighty-seven thousand, nine hundred eighty-one".