21050291 has 2 divisors, whose sum is σ = 21050292. Its totient is φ = 21050290.

The previous prime is 21050287. The next prime is 21050297. The reversal of 21050291 is 19205012.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21050291 - 2² = 21050287 is a prime.

It is a super-2 number, since 2×21050291² = 886229502369362, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21050297) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10525145 + 10525146.

It is an arithmetic number, because the mean of its divisors is an integer number (10525146).

Almost surely, 2^21050291 is an apocalyptic number.

21050291 is a deficient number, since it is larger than the sum of its proper divisors (1).

21050291 is an equidigital number, since it uses as much as digits as its factorization.

21050291 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 180, while the sum is 20.

The square root of 21050291 is about 4588.0596116441. The cubic root of 21050291 is about 276.1124786598.

The spelling of 21050291 in words is "twenty-one million, fifty thousand, two hundred ninety-one".