21616061 has 8 divisors (see below), whose sum is σ = 23446584. Its totient is φ = 19847680.

The previous prime is 21616051. The next prime is 21616069. The reversal of 21616061 is 16061612.

It can be written as a sum of positive squares in 4 ways, for example, as 280900 + 21335161 = 530^2 + 4619^2 .

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 21616061 - 2²² = 17421757 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21616069) 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, 14810 + ... + 16203.

It is an arithmetic number, because the mean of its divisors is an integer number (2930823).

Almost surely, 2^21616061 is an apocalyptic number.

It is an amenable number.

21616061 is a deficient number, since it is larger than the sum of its proper divisors (1830523).

21616061 is a wasteful number, since it uses less digits than its factorization.

21616061 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 31071.

The product of its (nonzero) digits is 432, while the sum is 23.

The square root of 21616061 is about 4649.3075828558. The cubic root of 21616061 is about 278.5643393581.

Adding to 21616061 its reverse (16061612), we get a palindrome (37677673).

The spelling of 21616061 in words is "twenty-one million, six hundred sixteen thousand, sixty-one".