21080351 has 4 divisors (see below), whose sum is σ = 21996912. Its totient is φ = 20163792.

The previous prime is 21080333. The next prime is 21080369. The reversal of 21080351 is 15308012.

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 (21080333) and next prime (21080369).

It is a cyclic number.

It is not a de Polignac number, because 21080351 - 2¹⁰ = 21079327 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 (21080321) 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, 458246 + ... + 458291.

It is an arithmetic number, because the mean of its divisors is an integer number (5499228).

Almost surely, 2^21080351 is an apocalyptic number.

21080351 is a deficient number, since it is larger than the sum of its proper divisors (916561).

21080351 is an equidigital number, since it uses as much as digits as its factorization.

21080351 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 916560.

The product of its (nonzero) digits is 240, while the sum is 20.

The square root of 21080351 is about 4591.3343376409. The cubic root of 21080351 is about 276.2438464945.

Adding to 21080351 its reverse (15308012), we get a palindrome (36388363).

The spelling of 21080351 in words is "twenty-one million, eighty thousand, three hundred fifty-one".