21616583 has 2 divisors, whose sum is σ = 21616584. Its totient is φ = 21616582.

The previous prime is 21616559. The next prime is 21616591. The reversal of 21616583 is 38561612.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21616583 - 2⁸ = 21616327 is a prime.

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

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21616783) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10808291 + 10808292.

It is an arithmetic number, because the mean of its divisors is an integer number (10808292).

Almost surely, 2^21616583 is an apocalyptic number.

21616583 is a deficient number, since it is larger than the sum of its proper divisors (1).

21616583 is an equidigital number, since it uses as much as digits as its factorization.

21616583 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 8640, while the sum is 32.

The square root of 21616583 is about 4649.3637199083. The cubic root of 21616583 is about 278.5665816633.

The spelling of 21616583 in words is "twenty-one million, six hundred sixteen thousand, five hundred eighty-three".