28220640581 has 32 divisors (see below), whose sum is σ = 33606752256. Its totient is φ = 23196600000.

The previous prime is 28220640551. The next prime is 28220640593. The reversal of 28220640581 is 18504602282.

It is not a de Polignac number, because 28220640581 - 2⁶ = 28220640517 is a prime.

It is a super-2 number, since 2×28220640581² (a number of 22 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28220640551) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 5361491 + ... + 5366751.

It is an arithmetic number, because the mean of its divisors is an integer number (1050211008).

Almost surely, 2^28220640581 is an apocalyptic number.

It is an amenable number.

28220640581 is a deficient number, since it is larger than the sum of its proper divisors (5386111675).

28220640581 is a wasteful number, since it uses less digits than its factorization.

28220640581 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5633.

The product of its (nonzero) digits is 61440, while the sum is 38.

The spelling of 28220640581 in words is "twenty-eight billion, two hundred twenty million, six hundred forty thousand, five hundred eighty-one".