21251543145 has 16 divisors (see below), whose sum is σ = 38859964800. Its totient is φ = 9714991104.

The previous prime is 21251543143. The next prime is 21251543153. The reversal of 21251543145 is 54134515212.

It is not a de Polignac number, because 21251543145 - 2¹ = 21251543143 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21251543143) 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, 101197720 + ... + 101197929.

It is an arithmetic number, because the mean of its divisors is an integer number (2428747800).

Almost surely, 2^21251543145 is an apocalyptic number.

It is an amenable number.

21251543145 is a deficient number, since it is larger than the sum of its proper divisors (17608421655).

21251543145 is a wasteful number, since it uses less digits than its factorization.

21251543145 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 202395664.

The product of its digits is 24000, while the sum is 33.

The spelling of 21251543145 in words is "twenty-one billion, two hundred fifty-one million, five hundred forty-three thousand, one hundred forty-five".