21616043 has 4 divisors (see below), whose sum is σ = 21729408. Its totient is φ = 21502680.

The previous prime is 21616039. The next prime is 21616051. The reversal of 21616043 is 34061612.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21616043 - 2² = 21616039 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21616003) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 56396 + ... + 56777.

It is an arithmetic number, because the mean of its divisors is an integer number (5432352).

Almost surely, 2^21616043 is an apocalyptic number.

21616043 is a deficient number, since it is larger than the sum of its proper divisors (113365).

21616043 is a wasteful number, since it uses less digits than its factorization.

21616043 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 113364.

The product of its (nonzero) digits is 864, while the sum is 23.

The square root of 21616043 is about 4649.3056470832. The cubic root of 21616043 is about 278.5642620366.

Adding to 21616043 its reverse (34061612), we get a palindrome (55677655).

The spelling of 21616043 in words is "twenty-one million, six hundred sixteen thousand, forty-three".