21523696488 has 240 divisors, whose sum is σ = 70312570020. Its totient is φ = 6133542912.

The previous prime is 21523696477. The next prime is 21523696531. The reversal of 21523696488 is 88469632512.

21523696488 is a `hidden beast` number, since 2 + 152 + 3 + 6 + 9 + 6 + 488 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 19314884484 + 2208812004 = 138978^2 + 46998^2 .

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

It is an unprimeable number.

It is a polite number, since it can be written in 59 ways as a sum of consecutive naturals, for example, 17685256 + ... + 17686472.

Almost surely, 2^21523696488 is an apocalyptic number.

21523696488 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 21523696488, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (35156285010).

21523696488 is an abundant number, since it is smaller than the sum of its proper divisors (48788873532).

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

21523696488 is a wasteful number, since it uses less digits than its factorization.

21523696488 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1806 (or 1786 counting only the distinct ones).

The product of its digits is 4976640, while the sum is 54.

The spelling of 21523696488 in words is "twenty-one billion, five hundred twenty-three million, six hundred ninety-six thousand, four hundred eighty-eight".