1209981 has 4 divisors (see below), whose sum is σ = 1613312. Its totient is φ = 806652.

The previous prime is 1209979. The next prime is 1210003. The reversal of 1209981 is 1899021.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 1209981 - 2¹ = 1209979 is a prime.

It is a super-2 number, since 2×1209981² = 2928108040722, which contains 22 as substring.

It is a D-number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1209931) 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, 201661 + ... + 201666.

It is an arithmetic number, because the mean of its divisors is an integer number (403328).

2^1209981 is an apocalyptic number.

It is an amenable number.

1209981 is a deficient number, since it is larger than the sum of its proper divisors (403331).

1209981 is an equidigital number, since it uses as much as digits as its factorization.

1209981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 403330.

The product of its (nonzero) digits is 1296, while the sum is 30.

The square root of 1209981 is about 1099.9913636025. The cubic root of 1209981 is about 106.5596659205.

It can be divided in two parts, 120 and 9981, that added together give a palindrome (10101).

The spelling of 1209981 in words is "one million, two hundred nine thousand, nine hundred eighty-one".