1981403 has 2 divisors, whose sum is σ = 1981404. Its totient is φ = 1981402.

The previous prime is 1981393. The next prime is 1981409. The reversal of 1981403 is 3041891.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1981403 is a prime.

It is a super-3 number, since 3×1981403³ = 23336713976133413481, which contains 333 as substring.

It is a Sophie Germain prime.

It is not a weakly prime, because it can be changed into another prime (1981409) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 990701 + 990702.

It is an arithmetic number, because the mean of its divisors is an integer number (990702).

2^1981403 is an apocalyptic number.

1981403 is a deficient number, since it is larger than the sum of its proper divisors (1).

1981403 is an equidigital number, since it uses as much as digits as its factorization.

1981403 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 864, while the sum is 26.

The square root of 1981403 is about 1407.6231740065. The cubic root of 1981403 is about 125.6003757748.

The spelling of 1981403 in words is "one million, nine hundred eighty-one thousand, four hundred three".