21402443 has 8 divisors (see below), whose sum is σ = 22617600. Its totient is φ = 20211048.

The previous prime is 21402419. The next prime is 21402467. The reversal of 21402443 is 34420412.

It is an interprime number because it is at equal distance from previous prime (21402419) and next prime (21402467).

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 21402443 - 2⁸ = 21402187 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21432443) 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, 4073 + ... + 7706.

It is an arithmetic number, because the mean of its divisors is an integer number (2827200).

Almost surely, 2^21402443 is an apocalyptic number.

21402443 is a gapful number since it is divisible by the number (23) formed by its first and last digit.

21402443 is a deficient number, since it is larger than the sum of its proper divisors (1215157).

21402443 is a wasteful number, since it uses less digits than its factorization.

21402443 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11881.

The product of its (nonzero) digits is 768, while the sum is 20.

The square root of 21402443 is about 4626.2774452036. The cubic root of 21402443 is about 277.6436742140.

Adding to 21402443 its reverse (34420412), we get a palindrome (55822855).

The spelling of 21402443 in words is "twenty-one million, four hundred two thousand, four hundred forty-three".