440421021 has 6 divisors (see below), whose sum is σ = 636163710. Its totient is φ = 293614008.

The previous prime is 440421019. The next prime is 440421041. The reversal of 440421021 is 120124044.

It can be written as a sum of positive squares in only one way, i.e., 321305625 + 119115396 = 17925^2 + 10914^2 .

It is not a de Polignac number, because 440421021 - 2¹ = 440421019 is a prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 440420985 and 440421003.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (440421001) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 24467826 + ... + 24467843.

It is an arithmetic number, because the mean of its divisors is an integer number (106027285).

Almost surely, 2^440421021 is an apocalyptic number.

It is an amenable number.

440421021 is a deficient number, since it is larger than the sum of its proper divisors (195742689).

440421021 is a wasteful number, since it uses less digits than its factorization.

440421021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 48935675 (or 48935672 counting only the distinct ones).

The product of its (nonzero) digits is 256, while the sum is 18.

The square root of 440421021 is about 20986.2102581671. The cubic root of 440421021 is about 760.8330091875.

Adding to 440421021 its reverse (120124044), we get a palindrome (560545065).

It can be divided in two parts, 4404 and 21021, that added together give a triangular number (25425 = T₂₂₅).

The spelling of 440421021 in words is "four hundred forty million, four hundred twenty-one thousand, twenty-one".