21075899 has 8 divisors (see below), whose sum is σ = 22750560. Its totient is φ = 19408896.

The previous prime is 21075871. The next prime is 21075907. The reversal of 21075899 is 99857012.

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

It is not a de Polignac number, because 21075899 - 2¹² = 21071803 is a prime.

It is a super-3 number, since 3×21075899³ (a number of 23 digits) contains 333 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21075809) 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, 4667 + ... + 7995.

It is an arithmetic number, because the mean of its divisors is an integer number (2843820).

Almost surely, 2^21075899 is an apocalyptic number.

21075899 is a deficient number, since it is larger than the sum of its proper divisors (1674661).

21075899 is a wasteful number, since it uses less digits than its factorization.

21075899 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3829.

The product of its (nonzero) digits is 45360, while the sum is 41.

The square root of 21075899 is about 4590.8494856617. The cubic root of 21075899 is about 276.2243983017.

The spelling of 21075899 in words is "twenty-one million, seventy-five thousand, eight hundred ninety-nine".