1440641981 has 2 divisors, whose sum is σ = 1440641982. Its totient is φ = 1440641980.

The previous prime is 1440641929. The next prime is 1440641987. The reversal of 1440641981 is 1891460441.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1401379225 + 39262756 = 37435^2 + 6266^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1440641981 is a prime.

It is a super-2 number, since 2×1440641981² = 4150898634839208722, 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 (1440641987) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 720320990 + 720320991.

It is an arithmetic number, because the mean of its divisors is an integer number (720320991).

Almost surely, 2^1440641981 is an apocalyptic number.

It is an amenable number.

1440641981 is a deficient number, since it is larger than the sum of its proper divisors (1).

1440641981 is an equidigital number, since it uses as much as digits as its factorization.

1440641981 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 27648, while the sum is 38.

The square root of 1440641981 is about 37955.7898218440. The cubic root of 1440641981 is about 1129.4110228505.

The spelling of 1440641981 in words is "one billion, four hundred forty million, six hundred forty-one thousand, nine hundred eighty-one".