21456445623 has 4 divisors (see below), whose sum is σ = 28608594168. Its totient is φ = 14304297080.

The previous prime is 21456445579. The next prime is 21456445693. The reversal of 21456445623 is 32654465412.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21456445623 - 2¹⁶ = 21456380087 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21456445693) 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, 3576074268 + ... + 3576074273.

It is an arithmetic number, because the mean of its divisors is an integer number (7152148542).

Almost surely, 2^21456445623 is an apocalyptic number.

21456445623 is a deficient number, since it is larger than the sum of its proper divisors (7152148545).

21456445623 is an equidigital number, since it uses as much as digits as its factorization.

21456445623 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7152148544.

The product of its digits is 691200, while the sum is 42.

The spelling of 21456445623 in words is "twenty-one billion, four hundred fifty-six million, four hundred forty-five thousand, six hundred twenty-three".