21616141 has 2 divisors, whose sum is σ = 21616142. Its totient is φ = 21616140.

The previous prime is 21616139. The next prime is 21616157. The reversal of 21616141 is 14161612.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 15093225 + 6522916 = 3885^2 + 2554^2 .

It is a cyclic number.

It is not a de Polignac number, because 21616141 - 2¹ = 21616139 is a prime.

Together with 21616139, it forms a pair of twin primes.

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

It is a plaindrome in base 11.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21616171) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10808070 + 10808071.

It is an arithmetic number, because the mean of its divisors is an integer number (10808071).

Almost surely, 2^21616141 is an apocalyptic number.

It is an amenable number.

21616141 is a deficient number, since it is larger than the sum of its proper divisors (1).

21616141 is an equidigital number, since it uses as much as digits as its factorization.

21616141 is an evil number, because the sum of its binary digits is even.

The product of its digits is 288, while the sum is 22.

The square root of 21616141 is about 4649.3161862794. The cubic root of 21616141 is about 278.5646830088.

Adding to 21616141 its reverse (14161612), we get a palindrome (35777753).

The spelling of 21616141 in words is "twenty-one million, six hundred sixteen thousand, one hundred forty-one".