21230251 has 8 divisors (see below), whose sum is σ = 24855264. Its totient is φ = 17753280.

The previous prime is 21230249. The next prime is 21230273. The reversal of 21230251 is 15203212.

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

It is a cyclic number.

It is not a de Polignac number, because 21230251 - 2¹ = 21230249 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21230551) 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, 36700 + ... + 37273.

It is an arithmetic number, because the mean of its divisors is an integer number (3106908).

Almost surely, 2^21230251 is an apocalyptic number.

21230251 is a deficient number, since it is larger than the sum of its proper divisors (3625013).

21230251 is an equidigital number, since it uses as much as digits as its factorization.

21230251 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 74021.

The product of its (nonzero) digits is 120, while the sum is 16.

The square root of 21230251 is about 4607.6296509160. The cubic root of 21230251 is about 276.8970801945.

Adding to 21230251 its reverse (15203212), we get a palindrome (36433463).

The spelling of 21230251 in words is "twenty-one million, two hundred thirty thousand, two hundred fifty-one".