21397443 has 8 divisors (see below), whose sum is σ = 28722000. Its totient is φ = 14168928.

The previous prime is 21397427. The next prime is 21397451. The reversal of 21397443 is 34479312.

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

It is not a de Polignac number, because 21397443 - 2⁴ = 21397427 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21397423) 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, 23488 + ... + 24381.

It is an arithmetic number, because the mean of its divisors is an integer number (3590250).

Almost surely, 2^21397443 is an apocalyptic number.

21397443 is a deficient number, since it is larger than the sum of its proper divisors (7324557).

21397443 is a wasteful number, since it uses less digits than its factorization.

21397443 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 48021.

The product of its digits is 18144, while the sum is 33.

The square root of 21397443 is about 4625.7370223565. The cubic root of 21397443 is about 277.6220516593.

The spelling of 21397443 in words is "twenty-one million, three hundred ninety-seven thousand, four hundred forty-three".