1213981 has 2 divisors, whose sum is σ = 1213982. Its totient is φ = 1213980.

The previous prime is 1213951. The next prime is 1214011. The reversal of 1213981 is 1893121.

It is a balanced prime because it is at equal distance from previous prime (1213951) and next prime (1214011).

It can be written as a sum of positive squares in only one way, i.e., 737881 + 476100 = 859^2 + 690^2 .

It is a cyclic number.

It is not a de Polignac number, because 1213981 - 2⁹ = 1213469 is a prime.

It is a super-2 number, since 2×1213981² = 2947499736722, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1213921) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 606990 + 606991.

It is an arithmetic number, because the mean of its divisors is an integer number (606991).

2^1213981 is an apocalyptic number.

It is an amenable number.

1213981 is a deficient number, since it is larger than the sum of its proper divisors (1).

1213981 is an equidigital number, since it uses as much as digits as its factorization.

1213981 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 432, while the sum is 25.

The square root of 1213981 is about 1101.8080595095. The cubic root of 1213981 is about 106.6769597272.

The spelling of 1213981 in words is "one million, two hundred thirteen thousand, nine hundred eighty-one".