21548723580 has 144 divisors (see below), whose sum is σ = 66964060800. Its totient is φ = 5607321984.

The previous prime is 21548723549. The next prime is 21548723617. The reversal of 21548723580 is 8532784512.

21548723580 is a `hidden beast` number, since 2 + 1 + 5 + 48 + 7 + 23 + 580 = 666.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 1282071 + ... + 1298769.

It is an arithmetic number, because the mean of its divisors is an integer number (465028200).

Almost surely, 2^21548723580 is an apocalyptic number.

21548723580 is a gapful number since it is divisible by the number (20) 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 21548723580, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33482030400).

21548723580 is an abundant number, since it is smaller than the sum of its proper divisors (45415337220).

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

21548723580 is a wasteful number, since it uses less digits than its factorization.

21548723580 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16888 (or 16883 counting only the distinct ones).

The product of its (nonzero) digits is 537600, while the sum is 45.

The spelling of 21548723580 in words is "twenty-one billion, five hundred forty-eight million, seven hundred twenty-three thousand, five hundred eighty".