21442663 has 4 divisors (see below), whose sum is σ = 23392008. Its totient is φ = 19493320.

The previous prime is 21442657. The next prime is 21442667. The reversal of 21442663 is 36624412.

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

It is not a de Polignac number, because 21442663 - 2¹³ = 21434471 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21442667) 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, 974656 + ... + 974677.

It is an arithmetic number, because the mean of its divisors is an integer number (5848002).

Almost surely, 2^21442663 is an apocalyptic number.

21442663 is a deficient number, since it is larger than the sum of its proper divisors (1949345).

21442663 is a wasteful number, since it uses less digits than its factorization.

21442663 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1949344.

The product of its digits is 6912, while the sum is 28.

The square root of 21442663 is about 4630.6223123896. The cubic root of 21442663 is about 277.8174836693.

The spelling of 21442663 in words is "twenty-one million, four hundred forty-two thousand, six hundred sixty-three".