28721677 has 4 divisors (see below), whose sum is σ = 28845180. Its totient is φ = 28598176.

The previous prime is 28721669. The next prime is 28721699. The reversal of 28721677 is 77612782.

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 13205956 + 15515721 = 3634^2 + 3939^2 .

It is a cyclic number.

It is not a de Polignac number, because 28721677 - 2³ = 28721669 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28721617) 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 3 ways as a sum of consecutive naturals, for example, 61402 + ... + 61867.

It is an arithmetic number, because the mean of its divisors is an integer number (7211295).

Almost surely, 2^28721677 is an apocalyptic number.

It is an amenable number.

28721677 is a deficient number, since it is larger than the sum of its proper divisors (123503).

28721677 is a wasteful number, since it uses less digits than its factorization.

28721677 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 123502.

The product of its digits is 65856, while the sum is 40.

The square root of 28721677 is about 5359.2608632161. The cubic root of 28721677 is about 306.2456519166.

The spelling of 28721677 in words is "twenty-eight million, seven hundred twenty-one thousand, six hundred seventy-seven".