1981907 has 4 divisors (see below), whose sum is σ = 1999560. Its totient is φ = 1964256.

The previous prime is 1981901. The next prime is 1981919. The reversal of 1981907 is 7091891.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 7091891 = 1559 ⋅4549.

It is a cyclic number.

It is not a de Polignac number, because 1981907 - 2⁴ = 1981891 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 3 ways as a sum of consecutive naturals, for example, 8657 + ... + 8882.

It is an arithmetic number, because the mean of its divisors is an integer number (499890).

2^1981907 is an apocalyptic number.

1981907 is a deficient number, since it is larger than the sum of its proper divisors (17653).

1981907 is a wasteful number, since it uses less digits than its factorization.

1981907 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17652.

The product of its (nonzero) digits is 4536, while the sum is 35.

The square root of 1981907 is about 1407.8021878091. The cubic root of 1981907 is about 125.6110243275.

The spelling of 1981907 in words is "one million, nine hundred eighty-one thousand, nine hundred seven".