21189751488 has 84 divisors (see below), whose sum is σ = 60757460400. Its totient is φ = 7060824576.

The previous prime is 21189751441. The next prime is 21189751543. The reversal of 21189751488 is 88415798112.

21189751488 is a `hidden beast` number, since 2 + 11 + 89 + 75 + 1 + 488 = 666.

It is a Cunningham number, because it is equal to 145567²-1.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 2616181 + ... + 2624267.

It is an arithmetic number, because the mean of its divisors is an integer number (723303100).

Almost surely, 2^21189751488 is an apocalyptic number.

It is an amenable number.

21189751488 is an abundant number, since it is smaller than the sum of its proper divisors (39567708912).

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

21189751488 is a wasteful number, since it uses less digits than its factorization.

21189751488 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12654 (or 12641 counting only the distinct ones).

The product of its digits is 1290240, while the sum is 54.

The spelling of 21189751488 in words is "twenty-one billion, one hundred eighty-nine million, seven hundred fifty-one thousand, four hundred eighty-eight".