21521093 has 8 divisors (see below), whose sum is σ = 23517216. Its totient is φ = 19531600.

The previous prime is 21521083. The next prime is 21521111. The reversal of 21521093 is 39012512.

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

It is not a de Polignac number, because 21521093 - 2¹⁰ = 21520069 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21521033) 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, 7238 + ... + 9768.

It is an arithmetic number, because the mean of its divisors is an integer number (2939652).

Almost surely, 2^21521093 is an apocalyptic number.

It is an amenable number.

21521093 is a deficient number, since it is larger than the sum of its proper divisors (1996123).

21521093 is a wasteful number, since it uses less digits than its factorization.

21521093 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3315.

The product of its (nonzero) digits is 540, while the sum is 23.

The square root of 21521093 is about 4639.0832068416. The cubic root of 21521093 is about 278.1557922899.

The spelling of 21521093 in words is "twenty-one million, five hundred twenty-one thousand, ninety-three".