21516041 has 2 divisors, whose sum is σ = 21516042. Its totient is φ = 21516040.

The previous prime is 21516029. The next prime is 21516071. The reversal of 21516041 is 14061512.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 21196816 + 319225 = 4604^2 + 565^2 .

It is a cyclic number.

It is not a de Polignac number, because 21516041 - 2¹⁰ = 21515017 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (21516071) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10758020 + 10758021.

It is an arithmetic number, because the mean of its divisors is an integer number (10758021).

Almost surely, 2^21516041 is an apocalyptic number.

It is an amenable number.

21516041 is a deficient number, since it is larger than the sum of its proper divisors (1).

21516041 is an equidigital number, since it uses as much as digits as its factorization.

21516041 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 240, while the sum is 20.

The square root of 21516041 is about 4638.5386707453. The cubic root of 21516041 is about 278.1340252258.

Adding to 21516041 its reverse (14061512), we get a palindrome (35577553).

It can be divided in two parts, 2151 and 6041, that added together give a 13-th power (8192 = 2¹³).

The spelling of 21516041 in words is "twenty-one million, five hundred sixteen thousand, forty-one".