613981 has 2 divisors, whose sum is σ = 613982. Its totient is φ = 613980.

The previous prime is 613969. The next prime is 613993. The reversal of 613981 is 189316.

It is a happy number.

It is a balanced prime because it is at equal distance from previous prime (613969) and next prime (613993).

It can be written as a sum of positive squares in only one way, i.e., 586756 + 27225 = 766^2 + 165^2 .

It is a cyclic number.

It is not a de Polignac number, because 613981 - 2⁹ = 613469 is a prime.

It is a super-2 number, since 2×613981² = 753945336722, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (613181) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 306990 + 306991.

It is an arithmetic number, because the mean of its divisors is an integer number (306991).

2⁶¹³⁹⁸¹ is an apocalyptic number.

It is an amenable number.

613981 is a deficient number, since it is larger than the sum of its proper divisors (1).

613981 is an equidigital number, since it uses as much as digits as its factorization.

613981 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1296, while the sum is 28.

The square root of 613981 is about 783.5693970543. The cubic root of 613981 is about 84.9933558821.

The spelling of 613981 in words is "six hundred thirteen thousand, nine hundred eighty-one".