442639521 has 9 divisors (see below), whose sum is σ = 639459379. Its totient is φ = 295050936.

The previous prime is 442639507. The next prime is 442639537. The reversal of 442639521 is 125936244.

It is a happy number.

The square root of 442639521 is 21039.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 372683025 + 69956496 = 19305^2 + 8364^2 .

It is a tau number, because it is divible by the number of its divisors (9).

It is not a de Polignac number, because 442639521 - 2²⁷ = 308421793 is a prime.

It is a super-2 number, since 2×442639521² = 391859491102218882, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (442639541) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 59611 + ... + 66623.

Almost surely, 2^442639521 is an apocalyptic number.

442639521 is the 21039-th square number.

442639521 is the 10520-th centered octagonal number.

It is an amenable number.

442639521 is a deficient number, since it is larger than the sum of its proper divisors (196819858).

442639521 is an frugal number, since it uses more digits than its factorization.

442639521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14032 (or 7016 counting only the distinct ones).

The product of its digits is 51840, while the sum is 36.

The cubic root of 442639521 is about 762.1083659717.

Multiplying 442639521 by its sum of digits (36), we get a square (15935022756 = 126234²).

The spelling of 442639521 in words is "four hundred forty-two million, six hundred thirty-nine thousand, five hundred twenty-one".