21442423 has 8 divisors (see below), whose sum is σ = 23232528. Its totient is φ = 19711104.

The previous prime is 21442411. The next prime is 21442427. The reversal of 21442423 is 32424412.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21442423 - 2⁵ = 21442391 is a prime.

It is a super-2 number, since 2×21442423² = 919555008221858, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21442394 and 21442403.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21442427) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 13936 + ... + 15397.

It is an arithmetic number, because the mean of its divisors is an integer number (2904066).

Almost surely, 2^21442423 is an apocalyptic number.

21442423 is a deficient number, since it is larger than the sum of its proper divisors (1790105).

21442423 is a wasteful number, since it uses less digits than its factorization.

21442423 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 29393.

The product of its digits is 1536, while the sum is 22.

The square root of 21442423 is about 4630.5963978736. The cubic root of 21442423 is about 277.8164471618.

Adding to 21442423 its reverse (32424412), we get a palindrome (53866835).

The spelling of 21442423 in words is "twenty-one million, four hundred forty-two thousand, four hundred twenty-three".