28661474209 has 9 divisors (see below), whose sum is σ = 29042422353. Its totient is φ = 28285465572.

The previous prime is 28661474203. The next prime is 28661474269. The reversal of 28661474209 is 90247416682.

The square root of 28661474209 is 169297.

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

It is not a de Polignac number, because 28661474209 - 2³ = 28661474201 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28661474201) 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, 13373392 + ... + 13375534.

It is an arithmetic number, because the mean of its divisors is an integer number (3226935817).

Almost surely, 2^28661474209 is an apocalyptic number.

28661474209 is the 169297-th square number.

28661474209 is the 84649-th centered octagonal number.

It is an amenable number.

28661474209 is a deficient number, since it is larger than the sum of its proper divisors (380948144).

28661474209 is an frugal number, since it uses more digits than its factorization.

28661474209 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4444 (or 2222 counting only the distinct ones).

The product of its (nonzero) digits is 1161216, while the sum is 49.

Multiplying 28661474209 by its sum of digits (49), we get a square (1404412236241 = 1185079²).

The spelling of 28661474209 in words is "twenty-eight billion, six hundred sixty-one million, four hundred seventy-four thousand, two hundred nine".