1981840197 has 8 divisors (see below), whose sum is σ = 2667149856. Its totient is φ = 1308878672.

The previous prime is 1981840151. The next prime is 1981840279. The reversal of 1981840197 is 7910481891.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 1981840197 - 2¹⁶ = 1981774661 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1981840097) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3086658 + ... + 3087299.

It is an arithmetic number, because the mean of its divisors is an integer number (333393732).

Almost surely, 2^1981840197 is an apocalyptic number.

It is an amenable number.

1981840197 is a deficient number, since it is larger than the sum of its proper divisors (685309659).

1981840197 is a wasteful number, since it uses less digits than its factorization.

1981840197 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6174067.

The product of its (nonzero) digits is 145152, while the sum is 48.

The square root of 1981840197 is about 44517.8637964582. The cubic root of 1981840197 is about 1256.0961301209.

The spelling of 1981840197 in words is "one billion, nine hundred eighty-one million, eight hundred forty thousand, one hundred ninety-seven".