669872421 has 12 divisors (see below), whose sum is σ = 1000959180. Its totient is φ = 431182080.

The previous prime is 669872419. The next prime is 669872431. The reversal of 669872421 is 124278966.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 552908196 + 116964225 = 23514^2 + 10815^2 .

It is not a de Polignac number, because 669872421 - 2¹ = 669872419 is a prime.

It is a hoax number, since the sum of its digits (45) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (669872431) 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 11 ways as a sum of consecutive naturals, for example, 1283020 + ... + 1283541.

It is an arithmetic number, because the mean of its divisors is an integer number (83413265).

Almost surely, 2^669872421 is an apocalyptic number.

It is an amenable number.

669872421 is a deficient number, since it is larger than the sum of its proper divisors (331086759).

669872421 is a wasteful number, since it uses less digits than its factorization.

669872421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2566596 (or 2566593 counting only the distinct ones).

The product of its digits is 290304, while the sum is 45.

The square root of 669872421 is about 25881.8936903774. The cubic root of 669872421 is about 874.9784684770.

The spelling of 669872421 in words is "six hundred sixty-nine million, eight hundred seventy-two thousand, four hundred twenty-one".