21916045 has 4 divisors (see below), whose sum is σ = 26299260. Its totient is φ = 17532832.

The previous prime is 21916021. The next prime is 21916051. The reversal of 21916045 is 54061912.

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 5900041 + 16016004 = 2429^2 + 4002^2 .

It is a cyclic number.

It is not a de Polignac number, because 21916045 - 2⁷ = 21915917 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2191600 + ... + 2191609.

It is an arithmetic number, because the mean of its divisors is an integer number (6574815).

Almost surely, 2^21916045 is an apocalyptic number.

It is an amenable number.

21916045 is a deficient number, since it is larger than the sum of its proper divisors (4383215).

21916045 is an equidigital number, since it uses as much as digits as its factorization.

21916045 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4383214.

The product of its (nonzero) digits is 2160, while the sum is 28.

The square root of 21916045 is about 4681.4575721670. The cubic root of 21916045 is about 279.8470465646.

Adding to 21916045 its reverse (54061912), we get a palindrome (75977957).

The spelling of 21916045 in words is "twenty-one million, nine hundred sixteen thousand, forty-five".