21521241273 has 16 divisors (see below), whose sum is σ = 34723347840. Its totient is φ = 11574448896.

The previous prime is 21521241263. The next prime is 21521241277. The reversal of 21521241273 is 37214212512.

It is not a de Polignac number, because 21521241273 - 2⁴ = 21521241257 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21521241273.

It is not an unprimeable number, because it can be changed into a prime (21521241277) by changing a digit.

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 15 ways as a sum of consecutive naturals, for example, 30141438 + ... + 30142151.

It is an arithmetic number, because the mean of its divisors is an integer number (2170209240).

Almost surely, 2^21521241273 is an apocalyptic number.

It is an amenable number.

21521241273 is a deficient number, since it is larger than the sum of its proper divisors (13202106567).

21521241273 is a wasteful number, since it uses less digits than its factorization.

21521241273 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 60283616.

The product of its digits is 6720, while the sum is 30.

Adding to 21521241273 its reverse (37214212512), we get a palindrome (58735453785).

The spelling of 21521241273 in words is "twenty-one billion, five hundred twenty-one million, two hundred forty-one thousand, two hundred seventy-three".