21673753 has 2 divisors, whose sum is σ = 21673754. Its totient is φ = 21673752.

The previous prime is 21673741. The next prime is 21673787. The reversal of 21673753 is 35737612.

It is an a-pointer prime, because the next prime (21673787) can be obtained adding 21673753 to its sum of digits (34).

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20358144 + 1315609 = 4512^2 + 1147^2 .

It is a cyclic number.

It is not a de Polignac number, because 21673753 - 2⁹ = 21673241 is a prime.

It is equal to p_1369870 and since 21673753 and 1369870 have the same sum of digits, it is a Honaker prime.

It is not a weakly prime, because it can be changed into another prime (21673703) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10836876 + 10836877.

It is an arithmetic number, because the mean of its divisors is an integer number (10836877).

Almost surely, 2^21673753 is an apocalyptic number.

It is an amenable number.

21673753 is a deficient number, since it is larger than the sum of its proper divisors (1).

21673753 is an equidigital number, since it uses as much as digits as its factorization.

21673753 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 26460, while the sum is 34.

The square root of 21673753 is about 4655.5078133325. The cubic root of 21673753 is about 278.8119431741.

The spelling of 21673753 in words is "twenty-one million, six hundred seventy-three thousand, seven hundred fifty-three".