21528875 has 16 divisors (see below), whose sum is σ = 27799200. Its totient is φ = 16626400.

The previous prime is 21528869. The next prime is 21528887. The reversal of 21528875 is 57882512.

It is a happy number.

It is not a de Polignac number, because 21528875 - 2⁶ = 21528811 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 656 + ... + 6594.

It is an arithmetic number, because the mean of its divisors is an integer number (1737450).

Almost surely, 2^21528875 is an apocalyptic number.

21528875 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

21528875 is a deficient number, since it is larger than the sum of its proper divisors (6270325).

21528875 is an equidigital number, since it uses as much as digits as its factorization.

21528875 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5983 (or 5973 counting only the distinct ones).

The product of its digits is 44800, while the sum is 38.

The square root of 21528875 is about 4639.9218743423. The cubic root of 21528875 is about 278.1893151772.

The spelling of 21528875 in words is "twenty-one million, five hundred twenty-eight thousand, eight hundred seventy-five".