21516029 has 2 divisors, whose sum is σ = 21516030. Its totient is φ = 21516028.

The previous prime is 21515983. The next prime is 21516041. The reversal of 21516029 is 92061512.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 18619225 + 2896804 = 4315^2 + 1702^2 .

It is a cyclic number.

It is not a de Polignac number, because 21516029 - 2¹⁶ = 21450493 is a prime.

It is a Chen prime.

It is a zygodrome in base 9.

It is a junction number, because it is equal to n+sod(n) for n = 21515989 and 21516007.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21516629) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10758014 + 10758015.

It is an arithmetic number, because the mean of its divisors is an integer number (10758015).

Almost surely, 2^21516029 is an apocalyptic number.

It is an amenable number.

21516029 is a deficient number, since it is larger than the sum of its proper divisors (1).

21516029 is an equidigital number, since it uses as much as digits as its factorization.

21516029 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1080, while the sum is 26.

The square root of 21516029 is about 4638.5373772343. The cubic root of 21516029 is about 278.1339735185.

The spelling of 21516029 in words is "twenty-one million, five hundred sixteen thousand, twenty-nine".