21216106512240 has 80 divisors (see below), whose sum is σ = 65805851774976. Its totient is φ = 5654538374400.

The previous prime is 21216106512233. The next prime is 21216106512247. The reversal of 21216106512240 is 4221560161212.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (21216106512233) and next prime (21216106512247).

It is a tau number, because it is divible by the number of its divisors (80).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21216106512247) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 23700496 + ... + 24579375.

Almost surely, 2^{21216106512240} is an apocalyptic number.

21216106512240 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21216106512240 is an abundant number, since it is smaller than the sum of its proper divisors (44589745262736).

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

21216106512240 is a wasteful number, since it uses less digits than its factorization.

21216106512240 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 48281718 (or 48281712 counting only the distinct ones).

The product of its (nonzero) digits is 11520, while the sum is 33.

Adding to 21216106512240 its reverse (4221560161212), we get a palindrome (25437666673452).

The spelling of 21216106512240 in words is "twenty-one trillion, two hundred sixteen billion, one hundred six million, five hundred twelve thousand, two hundred forty".