21023523145 has 4 divisors (see below), whose sum is σ = 25228227780. Its totient is φ = 16818818512.

The previous prime is 21023523139. The next prime is 21023523163. The reversal of 21023523145 is 54132532012.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 9429186816 + 11594336329 = 97104^2 + 107677^2 .

It is a cyclic number.

It is not a de Polignac number, because 21023523145 - 2¹¹ = 21023521097 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2102352310 + ... + 2102352319.

It is an arithmetic number, because the mean of its divisors is an integer number (6307056945).

Almost surely, 2^21023523145 is an apocalyptic number.

It is an amenable number.

21023523145 is a deficient number, since it is larger than the sum of its proper divisors (4204704635).

21023523145 is an equidigital number, since it uses as much as digits as its factorization.

21023523145 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4204704634.

The product of its (nonzero) digits is 7200, while the sum is 28.

The spelling of 21023523145 in words is "twenty-one billion, twenty-three million, five hundred twenty-three thousand, one hundred forty-five".