21521252543 has 16 divisors (see below), whose sum is σ = 25746739200. Its totient is φ = 17600284800.

The previous prime is 21521252531. The next prime is 21521252563. The reversal of 21521252543 is 34525212512.

It is not a de Polignac number, because 21521252543 - 2⁸ = 21521252287 is a prime.

It is a super-2 number, since 2×21521252543² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21521252563) 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, 683018 + ... + 713831.

It is an arithmetic number, because the mean of its divisors is an integer number (1609171200).

Almost surely, 2^21521252543 is an apocalyptic number.

21521252543 is a deficient number, since it is larger than the sum of its proper divisors (4225486657).

21521252543 is a wasteful number, since it uses less digits than its factorization.

21521252543 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1396958.

The product of its digits is 24000, while the sum is 32.

The spelling of 21521252543 in words is "twenty-one billion, five hundred twenty-one million, two hundred fifty-two thousand, five hundred forty-three".