1613981 has 2 divisors, whose sum is σ = 1613982. Its totient is φ = 1613980.

The previous prime is 1613959. The next prime is 1613987. The reversal of 1613981 is 1893161.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1585081 + 28900 = 1259^2 + 170^2 .

It is a cyclic number.

It is not a de Polignac number, because 1613981 - 2¹⁰ = 1612957 is a prime.

It is a super-2 number, since 2×1613981² = 5209869336722, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1613987) by changing a digit.

It is a good prime.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 806990 + 806991.

It is an arithmetic number, because the mean of its divisors is an integer number (806991).

2^1613981 is an apocalyptic number.

It is an amenable number.

1613981 is a deficient number, since it is larger than the sum of its proper divisors (1).

1613981 is an equidigital number, since it uses as much as digits as its factorization.

1613981 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1296, while the sum is 29.

The square root of 1613981 is about 1270.4255192651. The cubic root of 1613981 is about 117.3003944715.

The spelling of 1613981 in words is "one million, six hundred thirteen thousand, nine hundred eighty-one".