20007253809 has 9 divisors (see below), whose sum is σ = 28899979563. Its totient is φ = 13337886312.

The previous prime is 20007253807. The next prime is 20007253817. The reversal of 20007253809 is 90835270002.

It is a happy number.

The square root of 20007253809 is 141447.

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

20007253809 is a `hidden beast` number, since 200 + 0 + 72 + 5 + 380 + 9 = 666.

It can be written as a sum of positive squares in only one way, i.e., 41563809 + 19965690000 = 6447^2 + 141300^2 .

It is a tau number, because it is divible by the number of its divisors (9).

It is not a de Polignac number, because 20007253809 - 2¹ = 20007253807 is a prime.

It is not an unprimeable number, because it can be changed into a prime (20007253807) 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, 400767 + ... + 447915.

Almost surely, 2^20007253809 is an apocalyptic number.

20007253809 is the 141447-th square number.

20007253809 is the 70724-th centered octagonal number.

It is an amenable number.

20007253809 is a deficient number, since it is larger than the sum of its proper divisors (8892725754).

20007253809 is an frugal number, since it uses more digits than its factorization.

20007253809 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 94304 (or 47152 counting only the distinct ones).

The product of its (nonzero) digits is 30240, while the sum is 36.

Multiplying 20007253809 by its sum of digits (36), we get a square (720261137124 = 848682²).

The spelling of 20007253809 in words is "twenty billion, seven million, two hundred fifty-three thousand, eight hundred nine".