21418141 has 4 divisors (see below), whose sum is σ = 21511900. Its totient is φ = 21324384.

The previous prime is 21418139. The next prime is 21418151. The reversal of 21418141 is 14181412.

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

It can be written as a sum of positive squares in 2 ways, for example, as 15634116 + 5784025 = 3954^2 + 2405^2 .

It is a cyclic number.

It is not a de Polignac number, because 21418141 - 2¹ = 21418139 is a prime.

It is an alternating number because its digits alternate between even and odd.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21418151) 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, 46536 + ... + 46993.

It is an arithmetic number, because the mean of its divisors is an integer number (5377975).

Almost surely, 2^21418141 is an apocalyptic number.

It is an amenable number.

21418141 is a deficient number, since it is larger than the sum of its proper divisors (93759).

21418141 is an equidigital number, since it uses as much as digits as its factorization.

21418141 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 93758.

The product of its digits is 256, while the sum is 22.

The square root of 21418141 is about 4627.9737466844. The cubic root of 21418141 is about 277.7115385109.

Adding to 21418141 its reverse (14181412), we get a palindrome (35599553).

The spelling of 21418141 in words is "twenty-one million, four hundred eighteen thousand, one hundred forty-one".