21153075 has 24 divisors (see below), whose sum is σ = 35377200. Its totient is φ = 11151360.

The previous prime is 21153053. The next prime is 21153079. The reversal of 21153075 is 57035112.

It is not a de Polignac number, because 21153075 - 2⁵ = 21153043 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21153079) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 5091 + ... + 8259.

It is an arithmetic number, because the mean of its divisors is an integer number (1474050).

Almost surely, 2^21153075 is an apocalyptic number.

21153075 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

21153075 is a deficient number, since it is larger than the sum of its proper divisors (14224125).

21153075 is a wasteful number, since it uses less digits than its factorization.

21153075 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3271 (or 3266 counting only the distinct ones).

The product of its (nonzero) digits is 1050, while the sum is 24.

The square root of 21153075 is about 4599.2472210135. The cubic root of 21153075 is about 276.5611482905.

Adding to 21153075 its reverse (57035112), we get a palindrome (78188187).

The spelling of 21153075 in words is "twenty-one million, one hundred fifty-three thousand, seventy-five".