21323401 has 4 divisors (see below), whose sum is σ = 23261904. Its totient is φ = 19384900.

The previous prime is 21323371. The next prime is 21323417. The reversal of 21323401 is 10432312.

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 21323401 - 2⁷ = 21323273 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21323441) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 969235 + ... + 969256.

It is an arithmetic number, because the mean of its divisors is an integer number (5815476).

Almost surely, 2^21323401 is an apocalyptic number.

It is an amenable number.

21323401 is a deficient number, since it is larger than the sum of its proper divisors (1938503).

21323401 is a wasteful number, since it uses less digits than its factorization.

21323401 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1938502.

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

The square root of 21323401 is about 4617.7268217165. The cubic root of 21323401 is about 277.3014612131.

Adding to 21323401 its reverse (10432312), we get a palindrome (31755713).

The spelling of 21323401 in words is "twenty-one million, three hundred twenty-three thousand, four hundred one".