21620354616 has 192 divisors, whose sum is σ = 67580697600. Its totient is φ = 6116615424.

The previous prime is 21620354603. The next prime is 21620354647. The reversal of 21620354616 is 61645302612.

21620354616 is a `hidden beast` number, since 2 + 1 + 6 + 2 + 0 + 35 + 4 + 616 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 33108946 + ... + 33109598.

It is an arithmetic number, because the mean of its divisors is an integer number (351982800).

Almost surely, 2^21620354616 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21620354616, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33790348800).

21620354616 is an abundant number, since it is smaller than the sum of its proper divisors (45960342984).

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

21620354616 is a wasteful number, since it uses less digits than its factorization.

21620354616 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1218 (or 1211 counting only the distinct ones).

The product of its (nonzero) digits is 51840, while the sum is 36.

The spelling of 21620354616 in words is "twenty-one billion, six hundred twenty million, three hundred fifty-four thousand, six hundred sixteen".