21215186608 has 160 divisors (see below), whose sum is σ = 52846617600. Its totient is φ = 8178186240.

The previous prime is 21215186581. The next prime is 21215186609. The reversal of 21215186608 is 80668151212.

It is a happy number.

It is not an unprimeable number, because it can be changed into a prime (21215186609) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 5853885 + ... + 5857507.

It is an arithmetic number, because the mean of its divisors is an integer number (330291360).

Almost surely, 2^21215186608 is an apocalyptic number.

21215186608 is a gapful number since it is divisible by the number (28) 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 21215186608, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26423308800).

21215186608 is an abundant number, since it is smaller than the sum of its proper divisors (31631430992).

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

21215186608 is a wasteful number, since it uses less digits than its factorization.

21215186608 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3760 (or 3740 counting only the distinct ones).

The product of its (nonzero) digits is 46080, while the sum is 40.

The spelling of 21215186608 in words is "twenty-one billion, two hundred fifteen million, one hundred eighty-six thousand, six hundred eight".