21567673 has 2 divisors, whose sum is σ = 21567674. Its totient is φ = 21567672.

The previous prime is 21567653. The next prime is 21567691. The reversal of 21567673 is 37676512.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 16867449 + 4700224 = 4107^2 + 2168^2 .

It is a cyclic number.

It is not a de Polignac number, because 21567673 - 2¹⁷ = 21436601 is a prime.

It is not a weakly prime, because it can be changed into another prime (21567653) 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, 10783836 + 10783837.

It is an arithmetic number, because the mean of its divisors is an integer number (10783837).

Almost surely, 2^21567673 is an apocalyptic number.

It is an amenable number.

21567673 is a deficient number, since it is larger than the sum of its proper divisors (1).

21567673 is an equidigital number, since it uses as much as digits as its factorization.

21567673 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 52920, while the sum is 37.

The square root of 21567673 is about 4644.1008817639. The cubic root of 21567673 is about 278.3563267206.

The spelling of 21567673 in words is "twenty-one million, five hundred sixty-seven thousand, six hundred seventy-three".