191983309281 has 27 divisors (see below), whose sum is σ = 292710695121. Its totient is φ = 121236842664.

The previous prime is 191983309247. The next prime is 191983309313. The reversal of 191983309281 is 182903389191.

The square root of 191983309281 is 438159.

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

191983309281 is a `hidden beast` number, since 19 + 19 + 8 + 330 + 9 + 281 = 666.

It is not a de Polignac number, because 191983309281 - 2³⁵ = 157623570913 is a prime.

It is a super-2 number, since 2×191983309281² (a number of 23 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (191983329281) by changing a digit.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 24971220 + ... + 24978906.

Almost surely, 2^191983309281 is an apocalyptic number.

191983309281 is the 438159-th square number.

191983309281 is the 219080-th centered octagonal number.

It is an amenable number.

191983309281 is a deficient number, since it is larger than the sum of its proper divisors (100727385840).

191983309281 is an frugal number, since it uses more digits than its factorization.

191983309281 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15418 (or 7709 counting only the distinct ones).

The product of its (nonzero) digits is 839808, while the sum is 54.

It can be divided in two parts, 191983 and 309281, that added together give a square (501264 = 708²).

The spelling of 191983309281 in words is "one hundred ninety-one billion, nine hundred eighty-three million, three hundred nine thousand, two hundred eighty-one".