21588025640 has 32 divisors (see below), whose sum is σ = 48710690280. Its totient is φ = 8610742272.

The previous prime is 21588025631. The next prime is 21588025703. The reversal of 21588025640 is 4652088512.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 9642847204 + 11945178436 = 98198^2 + 109294^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 750329 + ... + 778568.

Almost surely, 2^21588025640 is an apocalyptic number.

21588025640 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21588025640 is an abundant number, since it is smaller than the sum of its proper divisors (27122664640).

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

21588025640 is a wasteful number, since it uses less digits than its factorization.

21588025640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1529261 (or 1529257 counting only the distinct ones).

The product of its (nonzero) digits is 153600, while the sum is 41.

The spelling of 21588025640 in words is "twenty-one billion, five hundred eighty-eight million, twenty-five thousand, six hundred forty".