20545501520021 has 8 divisors (see below), whose sum is σ = 20635369066200. Its totient is φ = 20455635271680.

The previous prime is 20545501519987. The next prime is 20545501520077. The reversal of 20545501520021 is 12002510554502.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 31495600900 + 20514005919121 = 177470^2 + 4529239^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 20545501520021 - 2³⁸ = 20270623613077 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 20545501520021.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20545501520521) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 45557525 + ... + 46006293.

It is an arithmetic number, because the mean of its divisors is an integer number (2579421133275).

Almost surely, 2^{20545501520021} is an apocalyptic number.

It is an amenable number.

20545501520021 is a deficient number, since it is larger than the sum of its proper divisors (89867546179).

20545501520021 is a wasteful number, since it uses less digits than its factorization.

20545501520021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 648919.

The product of its (nonzero) digits is 20000, while the sum is 32.

The spelling of 20545501520021 in words is "twenty trillion, five hundred forty-five billion, five hundred one million, five hundred twenty thousand, twenty-one".