28991025 has 72 divisors (see below), whose sum is σ = 60353280. Its totient is φ = 13029120.

The previous prime is 28991021. The next prime is 28991041. The reversal of 28991025 is 52019982.

It is not a de Polignac number, because 28991025 - 2² = 28991021 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (28991021) by changing a digit.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 124309 + ... + 124541.

It is an arithmetic number, because the mean of its divisors is an integer number (838240).

Almost surely, 2^28991025 is an apocalyptic number.

28991025 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

28991025 is an abundant number, since it is smaller than the sum of its proper divisors (31362255).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

28991025 is a wasteful number, since it uses less digits than its factorization.

28991025 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 335 (or 327 counting only the distinct ones).

The product of its (nonzero) digits is 12960, while the sum is 36.

The square root of 28991025 is about 5384.3314348209. The cubic root of 28991025 is about 307.1999849955.

The spelling of 28991025 in words is "twenty-eight million, nine hundred ninety-one thousand, twenty-five".