21541018 has 16 divisors (see below), whose sum is σ = 34292160. Its totient is φ = 10126336.

The previous prime is 21540983. The next prime is 21541019. The reversal of 21541018 is 81014512.

It is a self number, because there is not a number n which added to its sum of digits gives 21541018.

It is not an unprimeable number, because it can be changed into a prime (21541019) 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, 1255 + ... + 6682.

It is an arithmetic number, because the mean of its divisors is an integer number (2143260).

Almost surely, 2^21541018 is an apocalyptic number.

21541018 is a deficient number, since it is larger than the sum of its proper divisors (12751142).

21541018 is a wasteful number, since it uses less digits than its factorization.

21541018 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8021.

The product of its (nonzero) digits is 320, while the sum is 22.

The square root of 21541018 is about 4641.2302248434. The cubic root of 21541018 is about 278.2416080155.

The spelling of 21541018 in words is "twenty-one million, five hundred forty-one thousand, eighteen".