28091972 has 6 divisors (see below), whose sum is σ = 49160958. Its totient is φ = 14045984.

The previous prime is 28091971. The next prime is 28091977. The reversal of 28091972 is 27919082.

It can be written as a sum of positive squares in only one way, i.e., 28026436 + 65536 = 5294^2 + 256^2 .

It is not an unprimeable number, because it can be changed into a prime (28091971) 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 as a sum of consecutive naturals, namely, 3511493 + ... + 3511500.

It is an arithmetic number, because the mean of its divisors is an integer number (8193493).

Almost surely, 2^28091972 is an apocalyptic number.

It is an amenable number.

28091972 is a deficient number, since it is larger than the sum of its proper divisors (21068986).

28091972 is a wasteful number, since it uses less digits than its factorization.

28091972 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7022997 (or 7022995 counting only the distinct ones).

The product of its (nonzero) digits is 18144, while the sum is 38.

The square root of 28091972 is about 5300.1860344709. The cubic root of 28091972 is about 303.9910113917.

The spelling of 28091972 in words is "twenty-eight million, ninety-one thousand, nine hundred seventy-two".