421231521 has 12 divisors (see below), whose sum is σ = 567529872. Its totient is φ = 277907328.

The previous prime is 421231477. The next prime is 421231529. The reversal of 421231521 is 125132124.

It is not a de Polignac number, because 421231521 - 2⁹ = 421231009 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (421231529) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 20766 + ... + 35688.

It is an arithmetic number, because the mean of its divisors is an integer number (47294156).

Almost surely, 2^421231521 is an apocalyptic number.

It is an amenable number.

421231521 is a deficient number, since it is larger than the sum of its proper divisors (146298351).

421231521 is an equidigital number, since it uses as much as digits as its factorization.

421231521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15120 (or 15023 counting only the distinct ones).

The product of its digits is 480, while the sum is 21.

The square root of 421231521 is about 20523.9255748017. The cubic root of 421231521 is about 749.6184850725.

Adding to 421231521 its reverse (125132124), we get a palindrome (546363645).

The spelling of 421231521 in words is "four hundred twenty-one million, two hundred thirty-one thousand, five hundred twenty-one".