28961081 has 4 divisors (see below), whose sum is σ = 30664692. Its totient is φ = 27257472.

The previous prime is 28961077. The next prime is 28961123. The reversal of 28961081 is 18016982.

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

It can be written as a sum of positive squares in 2 ways, for example, as 15085456 + 13875625 = 3884^2 + 3725^2 .

It is a cyclic number.

It is not a de Polignac number, because 28961081 - 2² = 28961077 is a prime.

It is a super-2 number, since 2×28961081² = 1677488425377122, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28961041) 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, 851780 + ... + 851813.

It is an arithmetic number, because the mean of its divisors is an integer number (7666173).

Almost surely, 2^28961081 is an apocalyptic number.

It is an amenable number.

28961081 is a deficient number, since it is larger than the sum of its proper divisors (1703611).

28961081 is a wasteful number, since it uses less digits than its factorization.

28961081 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1703610.

The product of its (nonzero) digits is 6912, while the sum is 35.

The square root of 28961081 is about 5381.5500555137. The cubic root of 28961081 is about 307.0941825362.

The spelling of 28961081 in words is "twenty-eight million, nine hundred sixty-one thousand, eighty-one".