21545560272 has 80 divisors (see below), whose sum is σ = 56916357120. Its totient is φ = 7020053376.

The previous prime is 21545560261. The next prime is 21545560273. The reversal of 21545560272 is 27206554512.

It is a super-2 number, since 2×21545560272² (a number of 21 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21545560272.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21545560273) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1887093 + ... + 1898475.

It is an arithmetic number, because the mean of its divisors is an integer number (711454464).

Almost surely, 2^21545560272 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21545560272, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28458178560).

21545560272 is an abundant number, since it is smaller than the sum of its proper divisors (35370796848).

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

21545560272 is a wasteful number, since it uses less digits than its factorization.

21545560272 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12280 (or 12274 counting only the distinct ones).

The product of its (nonzero) digits is 168000, while the sum is 39.

The spelling of 21545560272 in words is "twenty-one billion, five hundred forty-five million, five hundred sixty thousand, two hundred seventy-two".