28691981201 has 4 divisors (see below), whose sum is σ = 30899056692. Its totient is φ = 26484905712.

The previous prime is 28691981177. The next prime is 28691981233. The reversal of 28691981201 is 10218919682.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 8523720976 + 20168260225 = 92324^2 + 142015^2 .

It is a cyclic number.

It is not a de Polignac number, because 28691981201 - 2²⁶ = 28624872337 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28691981701) 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, 1103537726 + ... + 1103537751.

It is an arithmetic number, because the mean of its divisors is an integer number (7724764173).

Almost surely, 2^28691981201 is an apocalyptic number.

It is an amenable number.

28691981201 is a deficient number, since it is larger than the sum of its proper divisors (2207075491).

28691981201 is a wasteful number, since it uses less digits than its factorization.

28691981201 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2207075490.

The product of its (nonzero) digits is 124416, while the sum is 47.

The spelling of 28691981201 in words is "twenty-eight billion, six hundred ninety-one million, nine hundred eighty-one thousand, two hundred one".