20981812201 has 9 divisors (see below), whose sum is σ = 24408593751. Its totient is φ = 17983541352.

The previous prime is 20981812193. The next prime is 20981812213. The reversal of 20981812201 is 10221818902.

The square root of 20981812201 is 144851.

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

It can be written as a sum of positive squares in only one way, i.e., 18891128025 + 2090684176 = 137445^2 + 45724^2 .

It is not a de Polignac number, because 20981812201 - 2³ = 20981812193 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20981812001) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 1003611 + ... + 1024303.

Almost surely, 2^20981812201 is an apocalyptic number.

20981812201 is the 144851-st square number.

20981812201 is the 72426-th centered octagonal number.

It is an amenable number.

20981812201 is a deficient number, since it is larger than the sum of its proper divisors (3426781550).

20981812201 is an frugal number, since it uses more digits than its factorization.

20981812201 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 41400 (or 20700 counting only the distinct ones).

The product of its (nonzero) digits is 4608, while the sum is 34.

The spelling of 20981812201 in words is "twenty billion, nine hundred eighty-one million, eight hundred twelve thousand, two hundred one".