440209981 has 2 divisors, whose sum is σ = 440209982. Its totient is φ = 440209980.

The previous prime is 440209969. The next prime is 440210003. The reversal of 440209981 is 189902044.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 330148900 + 110061081 = 18170^2 + 10491^2 .

It is a cyclic number.

It is not a de Polignac number, because 440209981 - 2¹⁹ = 439685693 is a prime.

It is a super-2 number, since 2×440209981² = 387569654744040722, 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 440209981.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (440209901) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 220104990 + 220104991.

It is an arithmetic number, because the mean of its divisors is an integer number (220104991).

Almost surely, 2^440209981 is an apocalyptic number.

It is an amenable number.

440209981 is a deficient number, since it is larger than the sum of its proper divisors (1).

440209981 is an equidigital number, since it uses as much as digits as its factorization.

440209981 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 20736, while the sum is 37.

The square root of 440209981 is about 20981.1815920839. The cubic root of 440209981 is about 760.7114649953.

The spelling of 440209981 in words is "four hundred forty million, two hundred nine thousand, nine hundred eighty-one".