198783581 has 2 divisors, whose sum is σ = 198783582. Its totient is φ = 198783580.

The previous prime is 198783569. The next prime is 198783587. The reversal of 198783581 is 185387891.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 197852356 + 931225 = 14066^2 + 965^2 .

It is a cyclic number.

It is not a de Polignac number, because 198783581 - 2¹⁸ = 198521437 is a prime.

It is a super-2 number, since 2×198783581² = 79029824150367122, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (198783587) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 99391790 + 99391791.

It is an arithmetic number, because the mean of its divisors is an integer number (99391791).

Almost surely, 2^198783581 is an apocalyptic number.

It is an amenable number.

198783581 is a deficient number, since it is larger than the sum of its proper divisors (1).

198783581 is an equidigital number, since it uses as much as digits as its factorization.

198783581 is an evil number, because the sum of its binary digits is even.

The product of its digits is 483840, while the sum is 50.

The square root of 198783581 is about 14099.0631249030. The cubic root of 198783581 is about 583.6155255786.

The spelling of 198783581 in words is "one hundred ninety-eight million, seven hundred eighty-three thousand, five hundred eighty-one".