423906921 has 9 divisors (see below), whose sum is σ = 612399229. Its totient is φ = 282563436.

The previous prime is 423906893. The next prime is 423906941. The reversal of 423906921 is 129609324.

The square root of 423906921 is 20589.

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

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

It is not a de Polignac number, because 423906921 - 2¹³ = 423898729 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (423906941) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 58336 + ... + 65198.

Almost surely, 2^423906921 is an apocalyptic number.

423906921 is the 20589-th square number.

423906921 is the 10295-th centered octagonal number.

It is an amenable number.

423906921 is a deficient number, since it is larger than the sum of its proper divisors (188492308).

423906921 is an frugal number, since it uses more digits than its factorization.

423906921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13732 (or 6866 counting only the distinct ones).

The product of its (nonzero) digits is 23328, while the sum is 36.

The cubic root of 423906921 is about 751.2021733428.

Multiplying 423906921 by its sum of digits (36), we get a square (15260649156 = 123534²).

The spelling of 423906921 in words is "four hundred twenty-three million, nine hundred six thousand, nine hundred twenty-one".