21655043 has 2 divisors, whose sum is σ = 21655044. Its totient is φ = 21655042.

The previous prime is 21655037. The next prime is 21655063. The reversal of 21655043 is 34055612.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21655043 - 2¹⁰ = 21654019 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (21655033) 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, 10827521 + 10827522.

It is an arithmetic number, because the mean of its divisors is an integer number (10827522).

Almost surely, 2^21655043 is an apocalyptic number.

21655043 is a deficient number, since it is larger than the sum of its proper divisors (1).

21655043 is an equidigital number, since it uses as much as digits as its factorization.

21655043 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3600, while the sum is 26.

The square root of 21655043 is about 4653.4979316639. The cubic root of 21655043 is about 278.7316913712.

The spelling of 21655043 in words is "twenty-one million, six hundred fifty-five thousand, forty-three".