19440661 has 2 divisors, whose sum is σ = 19440662. Its totient is φ = 19440660.

The previous prime is 19440649. The next prime is 19440721. The reversal of 19440661 is 16604491.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 17766225 + 1674436 = 4215^2 + 1294^2 .

It is an emirp because it is prime and its reverse (16604491) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 19440661 - 2⁹ = 19440149 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (19440461) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9720330 + 9720331.

It is an arithmetic number, because the mean of its divisors is an integer number (9720331).

Almost surely, 2^19440661 is an apocalyptic number.

It is an amenable number.

19440661 is a deficient number, since it is larger than the sum of its proper divisors (1).

19440661 is an equidigital number, since it uses as much as digits as its factorization.

19440661 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 5184, while the sum is 31.

The square root of 19440661 is about 4409.1564952948. The cubic root of 19440661 is about 268.8873322985.

The spelling of 19440661 in words is "nineteen million, four hundred forty thousand, six hundred sixty-one".