21748978488 has 32 divisors (see below), whose sum is σ = 54378092160. Its totient is φ = 7248906720.

The previous prime is 21748978487. The next prime is 21748978507. The reversal of 21748978488 is 88487984712.

It is a super-2 number, since 2×21748978488² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21748978483) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 219781 + ... + 302987.

It is an arithmetic number, because the mean of its divisors is an integer number (1699315380).

Almost surely, 2^21748978488 is an apocalyptic number.

It is an amenable number.

21748978488 is an abundant number, since it is smaller than the sum of its proper divisors (32629113672).

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

21748978488 is a wasteful number, since it uses less digits than its factorization.

21748978488 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 94107 (or 94103 counting only the distinct ones).

The product of its digits is 57802752, while the sum is 66.

The spelling of 21748978488 in words is "twenty-one billion, seven hundred forty-eight million, nine hundred seventy-eight thousand, four hundred eighty-eight".