21072075 has 24 divisors (see below), whose sum is σ = 35045376. Its totient is φ = 11172000.

The previous prime is 21072053. The next prime is 21072101. The reversal of 21072075 is 57027012.

It is not a de Polignac number, because 21072075 - 2⁵ = 21072043 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 13590 + ... + 15060.

It is an arithmetic number, because the mean of its divisors is an integer number (1460224).

Almost surely, 2^21072075 is an apocalyptic number.

21072075 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

21072075 is a deficient number, since it is larger than the sum of its proper divisors (13973301).

21072075 is a wasteful number, since it uses less digits than its factorization.

21072075 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1675 (or 1670 counting only the distinct ones).

The product of its (nonzero) digits is 980, while the sum is 24.

The square root of 21072075 is about 4590.4329861136. The cubic root of 21072075 is about 276.2076912882.

Adding to 21072075 its reverse (57027012), we get a palindrome (78099087).

The spelling of 21072075 in words is "twenty-one million, seventy-two thousand, seventy-five".