198215881 has 2 divisors, whose sum is σ = 198215882. Its totient is φ = 198215880.

The previous prime is 198215821. The next prime is 198215887. The reversal of 198215881 is 188512891.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 142205625 + 56010256 = 11925^2 + 7484^2 .

It is a cyclic number.

It is not a de Polignac number, because 198215881 - 2¹³ = 198207689 is a prime.

It is a super-2 number, since 2×198215881² = 78579070961212322, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (198215887) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 99107940 + 99107941.

It is an arithmetic number, because the mean of its divisors is an integer number (99107941).

Almost surely, 2^198215881 is an apocalyptic number.

It is an amenable number.

198215881 is a deficient number, since it is larger than the sum of its proper divisors (1).

198215881 is an equidigital number, since it uses as much as digits as its factorization.

198215881 is an evil number, because the sum of its binary digits is even.

The product of its digits is 46080, while the sum is 43.

The square root of 198215881 is about 14078.9161869797. The cubic root of 198215881 is about 583.0594192268.

The spelling of 198215881 in words is "one hundred ninety-eight million, two hundred fifteen thousand, eight hundred eighty-one".