28909961 has 8 divisors (see below), whose sum is σ = 29891400. Its totient is φ = 27941760.

The previous prime is 28909939. The next prime is 28909973. The reversal of 28909961 is 16990982.

It can be written as a sum of positive squares in 4 ways, for example, as 126736 + 28783225 = 356^2 + 5365^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 28909961 - 2¹⁴ = 28893577 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28909921) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1235 + ... + 7703.

It is an arithmetic number, because the mean of its divisors is an integer number (3736425).

Almost surely, 2^28909961 is an apocalyptic number.

It is an amenable number.

28909961 is a deficient number, since it is larger than the sum of its proper divisors (981439).

28909961 is a wasteful number, since it uses less digits than its factorization.

28909961 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6619.

The product of its (nonzero) digits is 69984, while the sum is 44.

The square root of 28909961 is about 5376.7983968157. The cubic root of 28909961 is about 306.9133893263.

The spelling of 28909961 in words is "twenty-eight million, nine hundred nine thousand, nine hundred sixty-one".