28071561 has 24 divisors (see below), whose sum is σ = 44562144. Its totient is φ = 15664320.

The previous prime is 28071541. The next prime is 28071577. The reversal of 28071561 is 16517082.

It is not a de Polignac number, because 28071561 - 2⁶ = 28071497 is a prime.

It is a hoax number, since the sum of its digits (30) coincides with the sum of the digits of its distinct prime factors.

It is not an unprimeable number, because it can be changed into a prime (28071541) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 4101 + ... + 8541.

It is an arithmetic number, because the mean of its divisors is an integer number (1856756).

Almost surely, 2^28071561 is an apocalyptic number.

28071561 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

28071561 is a deficient number, since it is larger than the sum of its proper divisors (16490583).

28071561 is a wasteful number, since it uses less digits than its factorization.

28071561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4501 (or 4494 counting only the distinct ones).

The product of its (nonzero) digits is 3360, while the sum is 30.

The square root of 28071561 is about 5298.2601861366. The cubic root of 28071561 is about 303.9173691914.

The spelling of 28071561 in words is "twenty-eight million, seventy-one thousand, five hundred sixty-one".