21540041421 has 16 divisors (see below), whose sum is σ = 29717348160. Its totient is φ = 13861612800.

The previous prime is 21540041387. The next prime is 21540041423. The reversal of 21540041421 is 12414004512.

It is not a de Polignac number, because 21540041421 - 2⁶ = 21540041357 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21540041391 and 21540041400.

It is a congruent number.

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

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 378021 + ... + 431253.

It is an arithmetic number, because the mean of its divisors is an integer number (1857334260).

Almost surely, 2^21540041421 is an apocalyptic number.

It is an amenable number.

21540041421 is a deficient number, since it is larger than the sum of its proper divisors (8177306739).

21540041421 is a wasteful number, since it uses less digits than its factorization.

21540041421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 57916.

The product of its (nonzero) digits is 1280, while the sum is 24.

Adding to 21540041421 its reverse (12414004512), we get a palindrome (33954045933).

The spelling of 21540041421 in words is "twenty-one billion, five hundred forty million, forty-one thousand, four hundred twenty-one".