21216055365240 has 32 divisors (see below), whose sum is σ = 63648166096080. Its totient is φ = 5657614764032.

The previous prime is 21216055365187. The next prime is 21216055365259. The reversal of 21216055365240 is 4256355061212.

It is a junction number, because it is equal to n+sod(n) for n = 21216055365192 and 21216055365201.

It is a congruent number.

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, 88400230569 + ... + 88400230808.

Almost surely, 2^{21216055365240} is an apocalyptic number.

21216055365240 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21216055365240 is an abundant number, since it is smaller than the sum of its proper divisors (42432110730840).

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

21216055365240 is a wasteful number, since it uses less digits than its factorization.

21216055365240 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 176800461391 (or 176800461387 counting only the distinct ones).

The product of its (nonzero) digits is 432000, while the sum is 42.

The spelling of 21216055365240 in words is "twenty-one trillion, two hundred sixteen billion, fifty-five million, three hundred sixty-five thousand, two hundred forty".