21321151 has 4 divisors (see below), whose sum is σ = 21341752. Its totient is φ = 21300552.

The previous prime is 21321133. The next prime is 21321169. The reversal of 21321151 is 15112312.

It is a semiprime because it is the product of two primes.

It is an interprime number because it is at equal distance from previous prime (21321133) and next prime (21321169).

It is a cyclic number.

It is not a de Polignac number, because 21321151 - 2⁹ = 21320639 is a prime.

It is a Duffinian number.

It is a plaindrome in base 16.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21321101) 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, 8661 + ... + 10846.

It is an arithmetic number, because the mean of its divisors is an integer number (5335438).

Almost surely, 2^21321151 is an apocalyptic number.

21321151 is a deficient number, since it is larger than the sum of its proper divisors (20601).

21321151 is a wasteful number, since it uses less digits than its factorization.

21321151 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20600.

The product of its digits is 60, while the sum is 16.

The square root of 21321151 is about 4617.4831889245. The cubic root of 21321151 is about 277.2917074496.

Adding to 21321151 its reverse (15112312), we get a palindrome (36433463).

The spelling of 21321151 in words is "twenty-one million, three hundred twenty-one thousand, one hundred fifty-one".