28661972 has 6 divisors (see below), whose sum is σ = 50158458. Its totient is φ = 14330984.

The previous prime is 28661959. The next prime is 28661981. The reversal of 28661972 is 27916682.

It can be written as a sum of positive squares in only one way, i.e., 14853316 + 13808656 = 3854^2 + 3716^2 .

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3582743 + ... + 3582750.

It is an arithmetic number, because the mean of its divisors is an integer number (8359743).

Almost surely, 2^28661972 is an apocalyptic number.

It is an amenable number.

28661972 is a deficient number, since it is larger than the sum of its proper divisors (21496486).

28661972 is a wasteful number, since it uses less digits than its factorization.

28661972 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7165497 (or 7165495 counting only the distinct ones).

The product of its digits is 72576, while the sum is 41.

The square root of 28661972 is about 5353.6877010151. The cubic root of 28661972 is about 306.0333026537.

The spelling of 28661972 in words is "twenty-eight million, six hundred sixty-one thousand, nine hundred seventy-two".