21126539 has 8 divisors (see below), whose sum is σ = 24177888. Its totient is φ = 18083520.

The previous prime is 21126533. The next prime is 21126551. The reversal of 21126539 is 93562112.

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

It is not a de Polignac number, because 21126539 - 2¹² = 21122443 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21126533) 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, 4949 + ... + 8169.

It is an arithmetic number, because the mean of its divisors is an integer number (3022236).

Almost surely, 2^21126539 is an apocalyptic number.

21126539 is a deficient number, since it is larger than the sum of its proper divisors (3051349).

21126539 is an equidigital number, since it uses as much as digits as its factorization.

21126539 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4165.

The product of its digits is 3240, while the sum is 29.

The square root of 21126539 is about 4596.3614957921. The cubic root of 21126539 is about 276.4454535659.

The spelling of 21126539 in words is "twenty-one million, one hundred twenty-six thousand, five hundred thirty-nine".