21617000000 has 98 divisors (see below), whose sum is σ = 53622087066. Its totient is φ = 8646400000.

The previous prime is 21616999981. The next prime is 21617000021. The reversal of 21617000000 is 71612.

It is a happy number.

It can be written as a sum of positive squares in 7 ways, for example, as 20699152384 + 917847616 = 143872^2 + 30296^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 13 ways as a sum of consecutive naturals, for example, 989192 + ... + 1010808.

Almost surely, 2^21617000000 is an apocalyptic number.

21617000000 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21617000000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26811043533).

21617000000 is an abundant number, since it is smaller than the sum of its proper divisors (32005087066).

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

21617000000 is an frugal number, since it uses more digits than its factorization.

21617000000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21659 (or 21624 counting only the distinct ones).

The product of its (nonzero) digits is 84, while the sum is 17.

Adding to 21617000000 its reverse (71612), we get a palindrome (21617071612).

The spelling of 21617000000 in words is "twenty-one billion, six hundred seventeen million", and thus it is an aban number.