28640321761 has 4 divisors (see below), whose sum is σ = 28642735792. Its totient is φ = 28637907732.

The previous prime is 28640321747. The next prime is 28640321771. The reversal of 28640321761 is 16712304682.

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 28640321761 - 2⁹ = 28640321249 is a prime.

It is a super-2 number, since 2×28640321761² (a number of 22 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28640321741) 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, 1189131 + ... + 1212976.

It is an arithmetic number, because the mean of its divisors is an integer number (7160683948).

Almost surely, 2^28640321761 is an apocalyptic number.

It is an amenable number.

28640321761 is a deficient number, since it is larger than the sum of its proper divisors (2414031).

28640321761 is a wasteful number, since it uses less digits than its factorization.

28640321761 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2414030.

The product of its (nonzero) digits is 96768, while the sum is 40.

The spelling of 28640321761 in words is "twenty-eight billion, six hundred forty million, three hundred twenty-one thousand, seven hundred sixty-one".