21091529 has 8 divisors (see below), whose sum is σ = 22157952. Its totient is φ = 20037600.

The previous prime is 21091523. The next prime is 21091547. The reversal of 21091529 is 92519012.

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

It is not a de Polignac number, because 21091529 - 2²⁴ = 4314313 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21091523) 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 7 ways as a sum of consecutive naturals, for example, 437 + ... + 6509.

It is an arithmetic number, because the mean of its divisors is an integer number (2769744).

Almost surely, 2^21091529 is an apocalyptic number.

It is an amenable number.

21091529 is a deficient number, since it is larger than the sum of its proper divisors (1066423).

21091529 is a wasteful number, since it uses less digits than its factorization.

21091529 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6247.

The product of its (nonzero) digits is 1620, while the sum is 29.

The square root of 21091529 is about 4592.5514694993. The cubic root of 21091529 is about 276.2926645952.

The spelling of 21091529 in words is "twenty-one million, ninety-one thousand, five hundred twenty-nine".