21419251 has 8 divisors (see below), whose sum is σ = 25767680. Its totient is φ = 17392968.

The previous prime is 21419207. The next prime is 21419267. The reversal of 21419251 is 15291412.

It is a happy number.

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 21419251 - 2¹¹ = 21417203 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21419291) 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, 80391 + ... + 80656.

It is an arithmetic number, because the mean of its divisors is an integer number (3220960).

Almost surely, 2^21419251 is an apocalyptic number.

21419251 is a deficient number, since it is larger than the sum of its proper divisors (4348429).

21419251 is a wasteful number, since it uses less digits than its factorization.

21419251 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 161073.

The product of its digits is 720, while the sum is 25.

The square root of 21419251 is about 4628.0936680236. The cubic root of 21419251 is about 277.7163359158.

The spelling of 21419251 in words is "twenty-one million, four hundred nineteen thousand, two hundred fifty-one".