21443075 has 6 divisors (see below), whose sum is σ = 26589444. Its totient is φ = 17154440.

The previous prime is 21443053. The next prime is 21443083. The reversal of 21443075 is 57034412.

It is not a de Polignac number, because 21443075 - 2⁸ = 21442819 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 428837 + ... + 428886.

It is an arithmetic number, because the mean of its divisors is an integer number (4431574).

Almost surely, 2^21443075 is an apocalyptic number.

21443075 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

21443075 is a deficient number, since it is larger than the sum of its proper divisors (5146369).

21443075 is an equidigital number, since it uses as much as digits as its factorization.

21443075 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 857733 (or 857728 counting only the distinct ones).

The product of its (nonzero) digits is 3360, while the sum is 26.

The square root of 21443075 is about 4630.6667986371. Note that the first 3 decimals coincide. The cubic root of 21443075 is about 277.8192629892.

Adding to 21443075 its reverse (57034412), we get a palindrome (78477487).

The spelling of 21443075 in words is "twenty-one million, four hundred forty-three thousand, seventy-five".