28156221270 has 160 divisors (see below), whose sum is σ = 80325232416. Its totient is φ = 7052313600.

The previous prime is 28156221263. The next prime is 28156221271. The reversal of 28156221270 is 7212265182.

It is a happy number.

28156221270 is a `hidden beast` number, since 2 + 8 + 1 + 5 + 622 + 1 + 27 + 0 = 666.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28156221271) by changing a digit.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 7860880 + ... + 7864460.

Almost surely, 2^28156221270 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 28156221270, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (40162616208).

28156221270 is an abundant number, since it is smaller than the sum of its proper divisors (52169011146).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

28156221270 is a wasteful number, since it uses less digits than its factorization.

28156221270 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4188 (or 4179 counting only the distinct ones).

The product of its (nonzero) digits is 26880, while the sum is 36.

The spelling of 28156221270 in words is "twenty-eight billion, one hundred fifty-six million, two hundred twenty-one thousand, two hundred seventy".