28911901225 has 27 divisors (see below), whose sum is σ = 37078338981. Its totient is φ = 22363003200.

The previous prime is 28911901223. The next prime is 28911901231. The reversal of 28911901225 is 52210911982.

The square root of 28911901225 is 170035.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in 4 ways, for example, as 3680484889 + 25231416336 = 60667^2 + 158844^2 .

It is not a de Polignac number, because 28911901225 - 2¹ = 28911901223 is a prime.

It is not an unprimeable number, because it can be changed into a prime (28911901223) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 26354877 + ... + 26355973.

Almost surely, 2^28911901225 is an apocalyptic number.

28911901225 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

28911901225 is the 170035-th square number.

28911901225 is the 85018-th centered octagonal number.

It is an amenable number.

28911901225 is a deficient number, since it is larger than the sum of its proper divisors (8166437756).

28911901225 is an frugal number, since it uses more digits than its factorization.

28911901225 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2266 (or 1133 counting only the distinct ones).

The product of its (nonzero) digits is 25920, while the sum is 40.

The spelling of 28911901225 in words is "twenty-eight billion, nine hundred eleven million, nine hundred one thousand, two hundred twenty-five".