21456401 has 4 divisors (see below), whose sum is σ = 22389312. Its totient is φ = 20523492.

The previous prime is 21456373. The next prime is 21456403. The reversal of 21456401 is 10465412.

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 21456401 - 2¹⁴ = 21440017 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (23), and also a Moran number because the ratio is a prime number: 932887 = 21456401 / (2 + 1 + 4 + 5 + 6 + 4 + 0 + 1).

It is a Duffinian number.

It is a plaindrome in base 11.

It is not an unprimeable number, because it can be changed into a prime (21456403) 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, 466421 + ... + 466466.

It is an arithmetic number, because the mean of its divisors is an integer number (5597328).

Almost surely, 2^21456401 is an apocalyptic number.

It is an amenable number.

21456401 is a deficient number, since it is larger than the sum of its proper divisors (932911).

21456401 is an equidigital number, since it uses as much as digits as its factorization.

21456401 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 932910.

The product of its (nonzero) digits is 960, while the sum is 23.

The square root of 21456401 is about 4632.1054608029. The cubic root of 21456401 is about 277.8768022000.

The spelling of 21456401 in words is "twenty-one million, four hundred fifty-six thousand, four hundred one".