21854539 has 12 divisors (see below), whose sum is σ = 25654104. Its totient is φ = 18561984.

The previous prime is 21854533. The next prime is 21854543. The reversal of 21854539 is 93545812.

It is not a de Polignac number, because 21854539 - 2⁵ = 21854507 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21854498 and 21854507.

It is not an unprimeable number, because it can be changed into a prime (21854533) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 3564 + ... + 7510.

It is an arithmetic number, because the mean of its divisors is an integer number (2137842).

Almost surely, 2^21854539 is an apocalyptic number.

21854539 is a deficient number, since it is larger than the sum of its proper divisors (3799565).

21854539 is a wasteful number, since it uses less digits than its factorization.

21854539 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4074 (or 4067 counting only the distinct ones).

The product of its digits is 43200, while the sum is 37.

The square root of 21854539 is about 4674.8838488245. The cubic root of 21854539 is about 279.5850102449.

It can be divided in two parts, 2185 and 4539, that added together give a square (6724 = 82²).

The spelling of 21854539 in words is "twenty-one million, eight hundred fifty-four thousand, five hundred thirty-nine".