21208292064 has 144 divisors (see below), whose sum is σ = 66061260720. Its totient is φ = 6424104960.

The previous prime is 21208292057. The next prime is 21208292089. The reversal of 21208292064 is 46029280212.

It is a tau number, because it is divible by the number of its divisors (144).

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 23 ways as a sum of consecutive naturals, for example, 67299 + ... + 216669.

It is an arithmetic number, because the mean of its divisors is an integer number (458758755).

Almost surely, 2^21208292064 is an apocalyptic number.

21208292064 is a gapful number since it is divisible by the number (24) 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 21208292064, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33030630360).

21208292064 is an abundant number, since it is smaller than the sum of its proper divisors (44852968656).

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

21208292064 is a wasteful number, since it uses less digits than its factorization.

21208292064 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 149433 (or 149422 counting only the distinct ones).

The product of its (nonzero) digits is 27648, while the sum is 36.

The spelling of 21208292064 in words is "twenty-one billion, two hundred eight million, two hundred ninety-two thousand, sixty-four".