1982226991 has 4 divisors (see below), whose sum is σ = 1983457512. Its totient is φ = 1980996472.

The previous prime is 1982226929. The next prime is 1982226997. The reversal of 1982226991 is 1996222891.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1996222891 = 13 ⋅153555607.

It is a cyclic number.

It is not a de Polignac number, because 1982226991 - 2⁹ = 1982226479 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1982226997) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 612841 + ... + 616066.

It is an arithmetic number, because the mean of its divisors is an integer number (495864378).

Almost surely, 2^1982226991 is an apocalyptic number.

1982226991 is a deficient number, since it is larger than the sum of its proper divisors (1230521).

1982226991 is a wasteful number, since it uses less digits than its factorization.

1982226991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1230520.

The product of its digits is 279936, while the sum is 49.

The square root of 1982226991 is about 44522.2078405822. The cubic root of 1982226991 is about 1256.1778418625.

The spelling of 1982226991 in words is "one billion, nine hundred eighty-two million, two hundred twenty-six thousand, nine hundred ninety-one".