21357773 has 2 divisors, whose sum is σ = 21357774. Its totient is φ = 21357772.

The previous prime is 21357719. The next prime is 21357779. The reversal of 21357773 is 37775312.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20187049 + 1170724 = 4493^2 + 1082^2 .

It is a cyclic number.

It is not a de Polignac number, because 21357773 - 2⁶ = 21357709 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21357779) 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, 10678886 + 10678887.

It is an arithmetic number, because the mean of its divisors is an integer number (10678887).

Almost surely, 2^21357773 is an apocalyptic number.

It is an amenable number.

21357773 is a deficient number, since it is larger than the sum of its proper divisors (1).

21357773 is an equidigital number, since it uses as much as digits as its factorization.

21357773 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 30870, while the sum is 35.

The square root of 21357773 is about 4621.4470677484. The cubic root of 21357773 is about 277.4503788125.

The spelling of 21357773 in words is "twenty-one million, three hundred fifty-seven thousand, seven hundred seventy-three".