21516404341 has 2 divisors, whose sum is σ = 21516404342. Its totient is φ = 21516404340.

The previous prime is 21516404323. The next prime is 21516404353. The reversal of 21516404341 is 14340461512.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 18946421316 + 2569983025 = 137646^2 + 50695^2 .

It is a cyclic number.

It is not a de Polignac number, because 21516404341 - 2¹⁵ = 21516371573 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21516404641) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10758202170 + 10758202171.

It is an arithmetic number, because the mean of its divisors is an integer number (10758202171).

Almost surely, 2^21516404341 is an apocalyptic number.

It is an amenable number.

21516404341 is a deficient number, since it is larger than the sum of its proper divisors (1).

21516404341 is an equidigital number, since it uses as much as digits as its factorization.

21516404341 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 11520, while the sum is 31.

Adding to 21516404341 its reverse (14340461512), we get a palindrome (35856865853).

The spelling of 21516404341 in words is "twenty-one billion, five hundred sixteen million, four hundred four thousand, three hundred forty-one".