21111234440 has 32 divisors (see below), whose sum is σ = 50294413080. Its totient is φ = 7947758592.

The previous prime is 21111234383. The next prime is 21111234449. The reversal of 21111234440 is 4443211112.

It can be written as a sum of positive squares in 4 ways, for example, as 12473762596 + 8637471844 = 111686^2 + 92938^2 .

It is a super-2 number, since 2×21111234440² (a number of 21 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21111234449) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 15522287 + ... + 15523646.

Almost surely, 2^21111234440 is an apocalyptic number.

21111234440 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21111234440 is an abundant number, since it is smaller than the sum of its proper divisors (29183178640).

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

21111234440 is a wasteful number, since it uses less digits than its factorization.

21111234440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 31045961 (or 31045957 counting only the distinct ones).

The product of its (nonzero) digits is 768, while the sum is 23.

Adding to 21111234440 its reverse (4443211112), we get a palindrome (25554445552).

The spelling of 21111234440 in words is "twenty-one billion, one hundred eleven million, two hundred thirty-four thousand, four hundred forty".