421523 has 4 divisors (see below), whose sum is σ = 423360. Its totient is φ = 419688.

The previous prime is 421517. The next prime is 421559. The reversal of 421523 is 325124.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 421523 - 2⁶ = 421459 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (421123) 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 3 ways as a sum of consecutive naturals, for example, 515 + ... + 1052.

It is an arithmetic number, because the mean of its divisors is an integer number (105840).

2⁴²¹⁵²³ is an apocalyptic number.

421523 is a deficient number, since it is larger than the sum of its proper divisors (1837).

421523 is a wasteful number, since it uses less digits than its factorization.

421523 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1836.

The product of its digits is 240, while the sum is 17.

The square root of 421523 is about 649.2480265661. The cubic root of 421523 is about 74.9791349366.

Adding to 421523 its reverse (325124), we get a palindrome (746647).

The spelling of 421523 in words is "four hundred twenty-one thousand, five hundred twenty-three".