21025249 has 4 divisors (see below), whose sum is σ = 24028864. Its totient is φ = 18021636.

The previous prime is 21025217. The next prime is 21025273. The reversal of 21025249 is 94252012.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21025249 - 2⁵ = 21025217 is a prime.

It is a super-3 number, since 3×21025249³ (a number of 23 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21025349) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1501797 + ... + 1501810.

It is an arithmetic number, because the mean of its divisors is an integer number (6007216).

Almost surely, 2^21025249 is an apocalyptic number.

It is an amenable number.

21025249 is a deficient number, since it is larger than the sum of its proper divisors (3003615).

21025249 is an equidigital number, since it uses as much as digits as its factorization.

21025249 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3003614.

The product of its (nonzero) digits is 1440, while the sum is 25.

The square root of 21025249 is about 4585.3297591340. The cubic root of 21025249 is about 276.0029449031.

The spelling of 21025249 in words is "twenty-one million, twenty-five thousand, two hundred forty-nine".