21143691543530 has 16 divisors (see below), whose sum is σ = 38074009637160. Its totient is φ = 8454062204352.

The previous prime is 21143691543521. The next prime is 21143691543589. The reversal of 21143691543530 is 3534519634112.

It is a Cunningham number, because it is equal to 4598227²+1.

It can be written as a sum of positive squares in 4 ways, for example, as 20732568209809 + 411123333721 = 4553303^2 + 641189^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 426775625 + ... + 426825164.

Almost surely, 2^{21143691543530} is an apocalyptic number.

21143691543530 is a deficient number, since it is larger than the sum of its proper divisors (16930318093630).

21143691543530 is a wasteful number, since it uses less digits than its factorization.

21143691543530 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 853603273.

The product of its (nonzero) digits is 1166400, while the sum is 47.

The spelling of 21143691543530 in words is "twenty-one trillion, one hundred forty-three billion, six hundred ninety-one million, five hundred forty-three thousand, five hundred thirty".