21421151 has 8 divisors (see below), whose sum is σ = 22713600. Its totient is φ = 20145240.

The previous prime is 21421133. The next prime is 21421159. The reversal of 21421151 is 15112412.

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 21421151 - 2¹⁸ = 21159007 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 (21421159) 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, 1415 + ... + 6696.

It is an arithmetic number, because the mean of its divisors is an integer number (2839200).

Almost surely, 2^21421151 is an apocalyptic number.

21421151 is a deficient number, since it is larger than the sum of its proper divisors (1292449).

21421151 is a wasteful number, since it uses less digits than its factorization.

21421151 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8269.

The product of its digits is 80, while the sum is 17.

The square root of 21421151 is about 4628.2989315730. The cubic root of 21421151 is about 277.7245473053.

Adding to 21421151 its reverse (15112412), we get a palindrome (36533563).

The spelling of 21421151 in words is "twenty-one million, four hundred twenty-one thousand, one hundred fifty-one".