199778235361 has 2 divisors, whose sum is σ = 199778235362. Its totient is φ = 199778235360.

The previous prime is 199778235347. The next prime is 199778235443. The reversal of 199778235361 is 163532877991.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 194957571600 + 4820663761 = 441540^2 + 69431^2 .

It is a cyclic number.

It is not a de Polignac number, because 199778235361 - 2³¹ = 197630751713 is a prime.

It is a super-2 number, since 2×199778235361² (a number of 23 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 199778235361.

It is not a weakly prime, because it can be changed into another prime (199778235661) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 99889117680 + 99889117681.

It is an arithmetic number, because the mean of its divisors is an integer number (99889117681).

Almost surely, 2^199778235361 is an apocalyptic number.

It is an amenable number.

199778235361 is a deficient number, since it is larger than the sum of its proper divisors (1).

199778235361 is an equidigital number, since it uses as much as digits as its factorization.

199778235361 is an evil number, because the sum of its binary digits is even.

The product of its digits is 17146080, while the sum is 61.

The spelling of 199778235361 in words is "one hundred ninety-nine billion, seven hundred seventy-eight million, two hundred thirty-five thousand, three hundred sixty-one".