21542234040 has 128 divisors (see below), whose sum is σ = 71842636800. Its totient is φ = 5741781120.

The previous prime is 21542234023. The next prime is 21542234059. The reversal of 21542234040 is 4043224512.

21542234040 is a `hidden beast` number, since 21 + 542 + 23 + 40 + 40 = 666.

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

It is a junction number, because it is equal to n+sod(n) for n = 21542233995 and 21542234013.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 3131805 + ... + 3138675.

It is an arithmetic number, because the mean of its divisors is an integer number (561270600).

Almost surely, 2^21542234040 is an apocalyptic number.

21542234040 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 21542234040, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (35921318400).

21542234040 is an abundant number, since it is smaller than the sum of its proper divisors (50300402760).

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

21542234040 is a wasteful number, since it uses less digits than its factorization.

21542234040 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9794 (or 9784 counting only the distinct ones).

The product of its (nonzero) digits is 7680, while the sum is 27.

Adding to 21542234040 its reverse (4043224512), we get a palindrome (25585458552).

The spelling of 21542234040 in words is "twenty-one billion, five hundred forty-two million, two hundred thirty-four thousand, forty".