21616361 has 8 divisors (see below), whose sum is σ = 23674560. Its totient is φ = 19614672.

The previous prime is 21616349. The next prime is 21616363. The reversal of 21616361 is 16361612.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21616361 - 2¹⁰ = 21615337 is a prime.

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

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 21616361.

It is not an unprimeable number, because it can be changed into a prime (21616363) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 13325 + ... + 14858.

It is an arithmetic number, because the mean of its divisors is an integer number (2959320).

Almost surely, 2^21616361 is an apocalyptic number.

It is an amenable number.

21616361 is a deficient number, since it is larger than the sum of its proper divisors (2058199).

21616361 is a wasteful number, since it uses less digits than its factorization.

21616361 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 28255.

The product of its digits is 1296, while the sum is 26.

The square root of 21616361 is about 4649.3398456125. The cubic root of 21616361 is about 278.5656280436.

Adding to 21616361 its reverse (16361612), we get a palindrome (37977973).

The spelling of 21616361 in words is "twenty-one million, six hundred sixteen thousand, three hundred sixty-one".