21540041420 has 48 divisors (see below), whose sum is σ = 49977321408. Its totient is φ = 7756615680.

The previous prime is 21540041387. The next prime is 21540041423. The reversal of 21540041420 is 2414004512.

It is a Harshad number since it is a multiple of its sum of digits (23).

It is not an unprimeable number, because it can be changed into a prime (21540041423) by changing a digit.

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 15 ways as a sum of consecutive naturals, for example, 1369421 + ... + 1385060.

It is an arithmetic number, because the mean of its divisors is an integer number (1041194196).

Almost surely, 2^21540041420 is an apocalyptic number.

21540041420 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21540041420 is an abundant number, since it is smaller than the sum of its proper divisors (28437279988).

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

21540041420 is a wasteful number, since it uses less digits than its factorization.

21540041420 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2754530 (or 2754528 counting only the distinct ones).

The product of its (nonzero) digits is 1280, while the sum is 23.

Adding to 21540041420 its reverse (2414004512), we get a palindrome (23954045932).

The spelling of 21540041420 in words is "twenty-one billion, five hundred forty million, forty-one thousand, four hundred twenty".