21756115440 has 240 divisors, whose sum is σ = 75226533408. Its totient is φ = 5630736384.

The previous prime is 21756115399. The next prime is 21756115453. The reversal of 21756115440 is 4451165712.

21756115440 is a `hidden beast` number, since 2 + 1 + 7 + 561 + 1 + 54 + 40 = 666.

It is a tau number, because it is divible by the number of its divisors (240).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 21756115395 and 21756115404.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 14571334 + ... + 14572826.

Almost surely, 2^21756115440 is an apocalyptic number.

21756115440 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 21756115440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (37613266704).

21756115440 is an abundant number, since it is smaller than the sum of its proper divisors (53470417968).

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

21756115440 is a wasteful number, since it uses less digits than its factorization.

21756115440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2096 (or 2087 counting only the distinct ones).

The product of its (nonzero) digits is 33600, while the sum is 36.

The spelling of 21756115440 in words is "twenty-one billion, seven hundred fifty-six million, one hundred fifteen thousand, four hundred forty".