28771561 has 16 divisors (see below), whose sum is σ = 35542528. Its totient is φ = 22680000.

The previous prime is 28771559. The next prime is 28771573. The reversal of 28771561 is 16517782.

It is not a de Polignac number, because 28771561 - 2¹ = 28771559 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 28771561.

It is not an unprimeable number, because it can be changed into a prime (28771511) by changing a digit.

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 in 15 ways as a sum of consecutive naturals, for example, 37936 + ... + 38686.

It is an arithmetic number, because the mean of its divisors is an integer number (2221408).

Almost surely, 2^28771561 is an apocalyptic number.

It is an amenable number.

28771561 is a deficient number, since it is larger than the sum of its proper divisors (6770967).

28771561 is a wasteful number, since it uses less digits than its factorization.

28771561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1192.

The product of its digits is 23520, while the sum is 37.

The square root of 28771561 is about 5363.9128441838. The cubic root of 28771561 is about 306.4228458686.

The spelling of 28771561 in words is "twenty-eight million, seven hundred seventy-one thousand, five hundred sixty-one".