21232401 has 4 divisors (see below), whose sum is σ = 28309872. Its totient is φ = 14154932.

The previous prime is 21232399. The next prime is 21232429. The reversal of 21232401 is 10423212.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21232401 - 2¹ = 21232399 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21232441) 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 3 ways as a sum of consecutive naturals, for example, 3538731 + ... + 3538736.

It is an arithmetic number, because the mean of its divisors is an integer number (7077468).

Almost surely, 2^21232401 is an apocalyptic number.

It is an amenable number.

21232401 is a deficient number, since it is larger than the sum of its proper divisors (7077471).

21232401 is an equidigital number, since it uses as much as digits as its factorization.

21232401 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7077470.

The product of its (nonzero) digits is 96, while the sum is 15.

The square root of 21232401 is about 4607.8629536912. The cubic root of 21232401 is about 276.9064270557.

Subtracting from 21232401 its sum of digits (15), we obtain a triangular number (21232386 = T₆₅₁₆).

Adding to 21232401 its reverse (10423212), we get a palindrome (31655613).

The spelling of 21232401 in words is "twenty-one million, two hundred thirty-two thousand, four hundred one".