1963981 has 2 divisors, whose sum is σ = 1963982. Its totient is φ = 1963980.

The previous prime is 1963921. The next prime is 1963999. The reversal of 1963981 is 1893691.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1946025 + 17956 = 1395^2 + 134^2 .

It is a cyclic number.

It is not a de Polignac number, because 1963981 - 2⁹ = 1963469 is a prime.

It is a super-2 number, since 2×1963981² = 7714442736722, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 1963981.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1963921) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 981990 + 981991.

It is an arithmetic number, because the mean of its divisors is an integer number (981991).

2^1963981 is an apocalyptic number.

It is an amenable number.

1963981 is a deficient number, since it is larger than the sum of its proper divisors (1).

1963981 is an equidigital number, since it uses as much as digits as its factorization.

1963981 is an evil number, because the sum of its binary digits is even.

The product of its digits is 11664, while the sum is 37.

The square root of 1963981 is about 1401.4210644913. The cubic root of 1963981 is about 125.2311668981.

It can be divided in two parts, 1963 and 981, that multiplied together give a triangular number (1925703 = T₁₉₆₂).

The spelling of 1963981 in words is "one million, nine hundred sixty-three thousand, nine hundred eighty-one".