21131434440 has 256 divisors, whose sum is σ = 75956832000. Its totient is φ = 5208053760.

The previous prime is 21131434433. The next prime is 21131434453. The reversal of 21131434440 is 4443413112.

21131434440 is a `hidden beast` number, since 2 + 1 + 1 + 314 + 344 + 4 + 0 = 666.

It is a super-2 number, since 2×21131434440² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 828762 + ... + 853878.

It is an arithmetic number, because the mean of its divisors is an integer number (296706375).

Almost surely, 2^21131434440 is an apocalyptic number.

21131434440 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 21131434440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (37978416000).

21131434440 is an abundant number, since it is smaller than the sum of its proper divisors (54825397560).

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

21131434440 is a wasteful number, since it uses less digits than its factorization.

21131434440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 25197 (or 25187 counting only the distinct ones).

The product of its (nonzero) digits is 4608, while the sum is 27.

Adding to 21131434440 its reverse (4443413112), we get a palindrome (25574847552).

The spelling of 21131434440 in words is "twenty-one billion, one hundred thirty-one million, four hundred thirty-four thousand, four hundred forty".