28991577 has 8 divisors (see below), whose sum is σ = 38816800. Its totient is φ = 19247040.

The previous prime is 28991563. The next prime is 28991581. The reversal of 28991577 is 77519982.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 28991577 - 2⁷ = 28991449 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28991507) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 19327 + ... + 20772.

It is an arithmetic number, because the mean of its divisors is an integer number (4852100).

Almost surely, 2^28991577 is an apocalyptic number.

It is an amenable number.

28991577 is a deficient number, since it is larger than the sum of its proper divisors (9825223).

28991577 is a wasteful number, since it uses less digits than its factorization.

28991577 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 40343.

The product of its digits is 317520, while the sum is 48.

The square root of 28991577 is about 5384.3826944228. The cubic root of 28991577 is about 307.2019347175.

The spelling of 28991577 in words is "twenty-eight million, nine hundred ninety-one thousand, five hundred seventy-seven".