1981207 has 4 divisors (see below), whose sum is σ = 1986160. Its totient is φ = 1976256.

The previous prime is 1981201. The next prime is 1981237. The reversal of 1981207 is 7021891.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 7021891 = 647 ⋅10853.

It is a cyclic number.

It is not a de Polignac number, because 1981207 - 2¹⁹ = 1456919 is a prime.

It is a Duffinian number.

It is a plaindrome in base 11.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1981201) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1818 + ... + 2695.

It is an arithmetic number, because the mean of its divisors is an integer number (496540).

2^1981207 is an apocalyptic number.

1981207 is a deficient number, since it is larger than the sum of its proper divisors (4953).

1981207 is an equidigital number, since it uses as much as digits as its factorization.

1981207 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4952.

The product of its (nonzero) digits is 1008, while the sum is 28.

The square root of 1981207 is about 1407.5535513791. The cubic root of 1981207 is about 125.5962341833.

The spelling of 1981207 in words is "one million, nine hundred eighty-one thousand, two hundred seven".