21401233 has 4 divisors (see below), whose sum is σ = 24458560. Its totient is φ = 18343908.

The previous prime is 21401203. The next prime is 21401251. The reversal of 21401233 is 33210412.

It is a happy number.

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 21401233 - 2¹³ = 21393041 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21401203) 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, 1528653 + ... + 1528666.

It is an arithmetic number, because the mean of its divisors is an integer number (6114640).

Almost surely, 2^21401233 is an apocalyptic number.

It is an amenable number.

21401233 is a deficient number, since it is larger than the sum of its proper divisors (3057327).

21401233 is an equidigital number, since it uses as much as digits as its factorization.

21401233 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3057326.

The product of its (nonzero) digits is 144, while the sum is 16.

The square root of 21401233 is about 4626.1466686650. The cubic root of 21401233 is about 277.6384418647.

Adding to 21401233 its reverse (33210412), we get a palindrome (54611645).

The spelling of 21401233 in words is "twenty-one million, four hundred one thousand, two hundred thirty-three".