21135773 has 2 divisors, whose sum is σ = 21135774. Its totient is φ = 21135772.

The previous prime is 21135767. The next prime is 21135791. The reversal of 21135773 is 37753112.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 21132409 + 3364 = 4597^2 + 58^2 .

It is a cyclic number.

It is not a de Polignac number, because 21135773 - 2¹⁰ = 21134749 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21135713) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10567886 + 10567887.

It is an arithmetic number, because the mean of its divisors is an integer number (10567887).

Almost surely, 2^21135773 is an apocalyptic number.

It is an amenable number.

21135773 is a deficient number, since it is larger than the sum of its proper divisors (1).

21135773 is an equidigital number, since it uses as much as digits as its factorization.

21135773 is an evil number, because the sum of its binary digits is even.

The product of its digits is 4410, while the sum is 29.

The square root of 21135773 is about 4597.3658762383. The cubic root of 21135773 is about 276.4857240127.

Adding to 21135773 its reverse (37753112), we get a palindrome (58888885).

The spelling of 21135773 in words is "twenty-one million, one hundred thirty-five thousand, seven hundred seventy-three".