21075199929 has 81 divisors (see below), whose sum is σ = 36756066789. Its totient is φ = 11602226160.

The previous prime is 21075199921. The next prime is 21075199979. The reversal of 21075199929 is 92999157012.

The square root of 21075199929 is 145173.

It is a perfect power (a square), and thus also a powerful number.

21075199929 is a `hidden beast` number, since 2 + 10 + 7 + 519 + 99 + 29 = 666.

It is not a de Polignac number, because 21075199929 - 2³ = 21075199921 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21075199921) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 80 ways as a sum of consecutive naturals, for example, 94507512 + ... + 94507734.

Almost surely, 2^21075199929 is an apocalyptic number.

21075199929 is the 145173-rd square number.

21075199929 is the 72587-th centered octagonal number.

It is an amenable number.

21075199929 is a deficient number, since it is larger than the sum of its proper divisors (15680866860).

21075199929 is an equidigital number, since it uses as much as digits as its factorization.

21075199929 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 528 (or 264 counting only the distinct ones).

The product of its (nonzero) digits is 918540, while the sum is 54.

The spelling of 21075199929 in words is "twenty-one billion, seventy-five million, one hundred ninety-nine thousand, nine hundred twenty-nine".