28661738909 has 4 divisors (see below), whose sum is σ = 28788002304. Its totient is φ = 28535475516.

The previous prime is 28661738869. The next prime is 28661738929. The reversal of 28661738909 is 90983716682.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 28661738909 - 2⁸ = 28661738653 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28661738929) 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, 63131357 + ... + 63131810.

It is an arithmetic number, because the mean of its divisors is an integer number (7197000576).

Almost surely, 2^28661738909 is an apocalyptic number.

It is an amenable number.

28661738909 is a deficient number, since it is larger than the sum of its proper divisors (126263395).

28661738909 is a wasteful number, since it uses less digits than its factorization.

28661738909 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 126263394.

The product of its (nonzero) digits is 7838208, while the sum is 59.

The spelling of 28661738909 in words is "twenty-eight billion, six hundred sixty-one million, seven hundred thirty-eight thousand, nine hundred nine".