20001321545 has 4 divisors (see below), whose sum is σ = 24001585860. Its totient is φ = 16001057232.

The previous prime is 20001321539. The next prime is 20001321553. The reversal of 20001321545 is 54512310002.

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 14466556729 + 5534764816 = 120277^2 + 74396^2 .

It is a cyclic number.

It is not a de Polignac number, because 20001321545 - 2¹² = 20001317449 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 20001321545.

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, 2000132150 + ... + 2000132159.

It is an arithmetic number, because the mean of its divisors is an integer number (6000396465).

Almost surely, 2^20001321545 is an apocalyptic number.

It is an amenable number.

20001321545 is a deficient number, since it is larger than the sum of its proper divisors (4000264315).

20001321545 is an equidigital number, since it uses as much as digits as its factorization.

20001321545 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4000264314.

The product of its (nonzero) digits is 1200, while the sum is 23.

Adding to 20001321545 its reverse (54512310002), we get a palindrome (74513631547).

The spelling of 20001321545 in words is "twenty billion, one million, three hundred twenty-one thousand, five hundred forty-five".