21027943 has 2 divisors, whose sum is σ = 21027944. Its totient is φ = 21027942.

The previous prime is 21027931. The next prime is 21027947. The reversal of 21027943 is 34972012.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21027943 is a prime.

It is a super-2 number, since 2×21027943² = 884348773622498, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21027947) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10513971 + 10513972.

It is an arithmetic number, because the mean of its divisors is an integer number (10513972).

Almost surely, 2^21027943 is an apocalyptic number.

21027943 is a deficient number, since it is larger than the sum of its proper divisors (1).

21027943 is an equidigital number, since it uses as much as digits as its factorization.

21027943 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3024, while the sum is 28.

The square root of 21027943 is about 4585.6235126752. The cubic root of 21027943 is about 276.0147326379.

Adding to 21027943 its reverse (34972012), we get a palindrome (55999955).

The spelling of 21027943 in words is "twenty-one million, twenty-seven thousand, nine hundred forty-three".