405072421209 has 15 divisors (see below), whose sum is σ = 605116741647. Its totient is φ = 270044462088.

The previous prime is 405072421181. The next prime is 405072421219. The reversal of 405072421209 is 902124270504.

The square root of 405072421209 is 636453.

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

405072421209 is a `hidden beast` number, since 4 + 0 + 507 + 24 + 2 + 120 + 9 = 666.

It can be written as a sum of positive squares in only one way, i.e., 205059537225 + 200012883984 = 452835^2 + 447228^2 .

It is not a de Polignac number, because 405072421209 - 2¹⁹ = 405071896921 is a prime.

It is not an unprimeable number, because it can be changed into a prime (405072421219) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 14 ways as a sum of consecutive naturals, for example, 5692719 + ... + 5763435.

Almost surely, 2^405072421209 is an apocalyptic number.

405072421209 is the 636453-rd square number.

405072421209 is the 318227-th centered octagonal number.

It is an amenable number.

405072421209 is a deficient number, since it is larger than the sum of its proper divisors (200044320438).

405072421209 is an frugal number, since it uses more digits than its factorization.

405072421209 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 141446 (or 70720 counting only the distinct ones).

The product of its (nonzero) digits is 40320, while the sum is 36.

Multiplying 405072421209 by its sum of digits (36), we get a square (14582607163524 = 3818718²).

It can be divided in two parts, 405072 and 421209, that added together give a square (826281 = 909²).

The spelling of 405072421209 in words is "four hundred five billion, seventy-two million, four hundred twenty-one thousand, two hundred nine".