21143691543529 has 27 divisors (see below), whose sum is σ = 21791004521349. Its totient is φ = 20515449583200.

The previous prime is 21143691543521. The next prime is 21143691543589. The reversal of 21143691543529 is 92534519634112.

The square root of 21143691543529 is 4598227.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in 4 ways, for example, as 11194411098025 + 9949280445504 = 3345805^2 + 3154248^2 .

It is not a de Polignac number, because 21143691543529 - 2³ = 21143691543521 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21143691543529.

It is not an unprimeable number, because it can be changed into a prime (21143691543521) by changing a digit.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 24614308702 + ... + 24614309560.

Almost surely, 2^{21143691543529} is an apocalyptic number.

21143691543529 is the 4598227-th square number.

21143691543529 is the 2299114-th centered octagonal number.

It is an amenable number.

21143691543529 is a deficient number, since it is larger than the sum of its proper divisors (647312977820).

21143691543529 is an frugal number, since it uses more digits than its factorization.

21143691543529 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2026 (or 1013 counting only the distinct ones).

The product of its digits is 6998400, while the sum is 55.

The spelling of 21143691543529 in words is "twenty-one trillion, one hundred forty-three billion, six hundred ninety-one million, five hundred forty-three thousand, five hundred twenty-nine".