199778634370249 has 9 divisors (see below), whose sum is σ = 219591562394631. Its totient is φ = 181616798993520.

The previous prime is 199778634370219. The next prime is 199778634370331. The reversal of 199778634370249 is 942073436877991.

The square root of 199778634370249 is 14134307.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 196202632345225 + 3576002025024 = 14007235^2 + 1891032^2 .

It is not a de Polignac number, because 199778634370249 - 2¹⁹ = 199778633845961 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (199778634370219) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 154834909 + ... + 156119845.

Almost surely, 2^{199778634370249} is an apocalyptic number.

199778634370249 is the 14134307-th square number.

199778634370249 is the 7067154-th centered octagonal number.

It is an amenable number.

199778634370249 is a deficient number, since it is larger than the sum of its proper divisors (19812928024382).

199778634370249 is an frugal number, since it uses more digits than its factorization.

199778634370249 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2569896 (or 1284948 counting only the distinct ones).

The product of its (nonzero) digits is 3456649728, while the sum is 79.

The spelling of 199778634370249 in words is "one hundred ninety-nine trillion, seven hundred seventy-eight billion, six hundred thirty-four million, three hundred seventy thousand, two hundred forty-nine".