21616121652 has 12 divisors (see below), whose sum is σ = 50437617216. Its totient is φ = 7205373880.

The previous prime is 21616121641. The next prime is 21616121731. The reversal of 21616121652 is 25612161612.

It is a tau number, because it is divible by the number of its divisors (12).

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

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 900671724 + ... + 900671747.

It is an arithmetic number, because the mean of its divisors is an integer number (4203134768).

Almost surely, 2^21616121652 is an apocalyptic number.

It is an amenable number.

21616121652 is an abundant number, since it is smaller than the sum of its proper divisors (28821495564).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21616121652 is a wasteful number, since it uses less digits than its factorization.

21616121652 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1801343478 (or 1801343476 counting only the distinct ones).

The product of its digits is 8640, while the sum is 33.

The spelling of 21616121652 in words is "twenty-one billion, six hundred sixteen million, one hundred twenty-one thousand, six hundred fifty-two".