1981971 has 12 divisors (see below), whose sum is σ = 2875600. Its totient is φ = 1315440.

The previous prime is 1981963. The next prime is 1981997. The reversal of 1981971 is 1791891.

It is not a de Polignac number, because 1981971 - 2³ = 1981963 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1981901) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 2826 + ... + 3456.

2^1981971 is an apocalyptic number.

1981971 is a deficient number, since it is larger than the sum of its proper divisors (893629).

1981971 is a wasteful number, since it uses less digits than its factorization.

1981971 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 986 (or 983 counting only the distinct ones).

The product of its digits is 4536, while the sum is 36.

The square root of 1981971 is about 1407.8249180917. The cubic root of 1981971 is about 125.6123763955.

The spelling of 1981971 in words is "one million, nine hundred eighty-one thousand, nine hundred seventy-one".