21211111240 has 96 divisors (see below), whose sum is σ = 53347896000. Its totient is φ = 7582298240.

The previous prime is 21211111147. The next prime is 21211111253. The reversal of 21211111240 is 4211111212.

It is a super-2 number, since 2×21211111240² (a number of 21 digits) contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 248421 + ... + 322699.

It is an arithmetic number, because the mean of its divisors is an integer number (555707250).

Almost surely, 2^21211111240 is an apocalyptic number.

21211111240 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 21211111240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26673948000).

21211111240 is an abundant number, since it is smaller than the sum of its proper divisors (32136784760).

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

21211111240 is a wasteful number, since it uses less digits than its factorization.

21211111240 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 74371 (or 74356 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 16.

Adding to 21211111240 its reverse (4211111212), we get a palindrome (25422222452).

The spelling of 21211111240 in words is "twenty-one billion, two hundred eleven million, one hundred eleven thousand, two hundred forty".