21373443 has 32 divisors (see below), whose sum is σ = 38976000. Its totient is φ = 11272608.

The previous prime is 21373411. The next prime is 21373447. The reversal of 21373443 is 34437312.

21373443 is a `hidden beast` number, since 213 + 7 + 3 + 443 = 666.

It is not a de Polignac number, because 21373443 - 2⁵ = 21373411 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is not an unprimeable number, because it can be changed into a prime (21373447) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1893 + ... + 6806.

It is an arithmetic number, because the mean of its divisors is an integer number (1218000).

Almost surely, 2^21373443 is an apocalyptic number.

21373443 is a deficient number, since it is larger than the sum of its proper divisors (17602557).

21373443 is a wasteful number, since it uses less digits than its factorization.

21373443 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8728 (or 8722 counting only the distinct ones).

The product of its digits is 6048, while the sum is 27.

The square root of 21373443 is about 4623.1421133251. The cubic root of 21373443 is about 277.5182164813.

The spelling of 21373443 in words is "twenty-one million, three hundred seventy-three thousand, four hundred forty-three".