21050331 has 4 divisors (see below), whose sum is σ = 28067112. Its totient is φ = 14033552.

The previous prime is 21050311. The next prime is 21050339. The reversal of 21050331 is 13305012.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 21050331 - 2⁷ = 21050203 is a prime.

It is a super-2 number, since 2×21050331² = 886232870419122, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21050331.

It is not an unprimeable number, because it can be changed into a prime (21050339) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3508386 + ... + 3508391.

It is an arithmetic number, because the mean of its divisors is an integer number (7016778).

Almost surely, 2^21050331 is an apocalyptic number.

21050331 is a deficient number, since it is larger than the sum of its proper divisors (7016781).

21050331 is an equidigital number, since it uses as much as digits as its factorization.

21050331 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7016780.

The product of its (nonzero) digits is 90, while the sum is 15.

The square root of 21050331 is about 4588.0639707833. The cubic root of 21050331 is about 276.1126535504.

Subtracting from 21050331 its sum of digits (15), we obtain a triangular number (21050316 = T₆₄₈₈).

Adding to 21050331 its reverse (13305012), we get a palindrome (34355343).

The spelling of 21050331 in words is "twenty-one million, fifty thousand, three hundred thirty-one".