21687098328 has 256 divisors, whose sum is σ = 71221248000. Its totient is φ = 5986161792.

The previous prime is 21687098309. The next prime is 21687098369. The reversal of 21687098328 is 82389078612.

It is a happy number.

21687098328 is a `hidden beast` number, since 2 + 168 + 70 + 98 + 328 = 666.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 5612125 + ... + 5615987.

It is an arithmetic number, because the mean of its divisors is an integer number (278208000).

Almost surely, 2^21687098328 is an apocalyptic number.

21687098328 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 21687098328, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (35610624000).

21687098328 is an abundant number, since it is smaller than the sum of its proper divisors (49534149672).

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

21687098328 is a wasteful number, since it uses less digits than its factorization.

21687098328 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4011 (or 4001 counting only the distinct ones).

The product of its (nonzero) digits is 2322432, while the sum is 54.

The spelling of 21687098328 in words is "twenty-one billion, six hundred eighty-seven million, ninety-eight thousand, three hundred twenty-eight".