21180043 has 2 divisors, whose sum is σ = 21180044. Its totient is φ = 21180042.

The previous prime is 21180017. The next prime is 21180053. The reversal of 21180043 is 34008112.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21180043 - 2⁹ = 21179531 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21180043.

It is not a weakly prime, because it can be changed into another prime (21180053) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10590021 + 10590022.

It is an arithmetic number, because the mean of its divisors is an integer number (10590022).

Almost surely, 2^21180043 is an apocalyptic number.

21180043 is a deficient number, since it is larger than the sum of its proper divisors (1).

21180043 is an equidigital number, since it uses as much as digits as its factorization.

21180043 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 192, while the sum is 19.

The square root of 21180043 is about 4602.1780713049. The cubic root of 21180043 is about 276.6786274083.

Adding to 21180043 its reverse (34008112), we get a palindrome (55188155).

The spelling of 21180043 in words is "twenty-one million, one hundred eighty thousand, forty-three".