21793539 has 4 divisors (see below), whose sum is σ = 29058056. Its totient is φ = 14529024.

The previous prime is 21793537. The next prime is 21793543. The reversal of 21793539 is 93539712.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 21793539 - 2¹ = 21793537 is a prime.

It is a Duffinian number.

It is a plaindrome in base 11.

It is a junction number, because it is equal to n+sod(n) for n = 21793497 and 21793506.

It is not an unprimeable number, because it can be changed into a prime (21793537) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3632254 + ... + 3632259.

It is an arithmetic number, because the mean of its divisors is an integer number (7264514).

Almost surely, 2^21793539 is an apocalyptic number.

21793539 is a deficient number, since it is larger than the sum of its proper divisors (7264517).

21793539 is an equidigital number, since it uses as much as digits as its factorization.

21793539 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7264516.

The product of its digits is 51030, while the sum is 39.

The square root of 21793539 is about 4668.3550636172. The cubic root of 21793539 is about 279.3246436173.

The spelling of 21793539 in words is "twenty-one million, seven hundred ninety-three thousand, five hundred thirty-nine".