21540121535 has 8 divisors (see below), whose sum is σ = 25850808720. Its totient is φ = 17230321984.

The previous prime is 21540121423. The next prime is 21540121543. The reversal of 21540121535 is 53512104512.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21540121535 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21540121498 and 21540121507.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 167297 + ... + 266586.

It is an arithmetic number, because the mean of its divisors is an integer number (3231351090).

Almost surely, 2^21540121535 is an apocalyptic number.

21540121535 is a deficient number, since it is larger than the sum of its proper divisors (4310687185).

21540121535 is an equidigital number, since it uses as much as digits as its factorization.

21540121535 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 443817.

The product of its (nonzero) digits is 6000, while the sum is 29.

The spelling of 21540121535 in words is "twenty-one billion, five hundred forty million, one hundred twenty-one thousand, five hundred thirty-five".