21051143 has 2 divisors, whose sum is σ = 21051144. Its totient is φ = 21051142.

The previous prime is 21051137. The next prime is 21051193. The reversal of 21051143 is 34115012.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21051143 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21051103) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10525571 + 10525572.

It is an arithmetic number, because the mean of its divisors is an integer number (10525572).

Almost surely, 2^21051143 is an apocalyptic number.

21051143 is a deficient number, since it is larger than the sum of its proper divisors (1).

21051143 is an equidigital number, since it uses as much as digits as its factorization.

21051143 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 120, while the sum is 17.

The square root of 21051143 is about 4588.1524604137. The cubic root of 21051143 is about 276.1162037811.

Adding to 21051143 its reverse (34115012), we get a palindrome (55166155).

The spelling of 21051143 in words is "twenty-one million, fifty-one thousand, one hundred forty-three".