18652772209 has 4 divisors (see below), whose sum is σ = 18653074804. Its totient is φ = 18652469616.

The previous prime is 18652772197. The next prime is 18652772251. The reversal of 18652772209 is 90227725681.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 90227725681 = 174491 ⋅517091.

It can be written as a sum of positive squares in 2 ways, for example, as 5416960000 + 13235812209 = 73600^2 + 115047^2 .

It is a cyclic number.

It is not a de Polignac number, because 18652772209 - 2¹³ = 18652764017 is a prime.

It is a super-2 number, since 2×18652772209² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18652772269) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 22002 + ... + 194395.

It is an arithmetic number, because the mean of its divisors is an integer number (4663268701).

Almost surely, 2^18652772209 is an apocalyptic number.

It is an amenable number.

18652772209 is a deficient number, since it is larger than the sum of its proper divisors (302595).

18652772209 is an equidigital number, since it uses as much as digits as its factorization.

18652772209 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 302594.

The product of its (nonzero) digits is 846720, while the sum is 49.

The spelling of 18652772209 in words is "eighteen billion, six hundred fifty-two million, seven hundred seventy-two thousand, two hundred nine".