28221595251 has 4 divisors (see below), whose sum is σ = 37628793672. Its totient is φ = 18814396832.

The previous prime is 28221595189. The next prime is 28221595301. The reversal of 28221595251 is 15259512282.

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

It is a cyclic number.

It is not a de Polignac number, because 28221595251 - 2²³ = 28213206643 is a prime.

It is a super-2 number, since 2×28221595251² (a number of 22 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (28221595651) 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, 4703599206 + ... + 4703599211.

It is an arithmetic number, because the mean of its divisors is an integer number (9407198418).

Almost surely, 2^28221595251 is an apocalyptic number.

28221595251 is a deficient number, since it is larger than the sum of its proper divisors (9407198421).

28221595251 is an equidigital number, since it uses as much as digits as its factorization.

28221595251 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9407198420.

The product of its digits is 144000, while the sum is 42.

The spelling of 28221595251 in words is "twenty-eight billion, two hundred twenty-one million, five hundred ninety-five thousand, two hundred fifty-one".