215664773 has 2 divisors, whose sum is σ = 215664774. Its totient is φ = 215664772.

The previous prime is 215664751. The next prime is 215664821. The reversal of 215664773 is 377466512.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 204118369 + 11546404 = 14287^2 + 3398^2 .

It is a cyclic number.

It is not a de Polignac number, because 215664773 - 2²⁶ = 148555909 is a prime.

It is a super-2 number, since 2×215664773² = 93022588626283058, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 215664773.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (215664733) 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, 107832386 + 107832387.

It is an arithmetic number, because the mean of its divisors is an integer number (107832387).

Almost surely, 2^215664773 is an apocalyptic number.

It is an amenable number.

215664773 is a deficient number, since it is larger than the sum of its proper divisors (1).

215664773 is an equidigital number, since it uses as much as digits as its factorization.

215664773 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 211680, while the sum is 41.

The square root of 215664773 is about 14685.5293741833. The cubic root of 215664773 is about 599.6894439156.

The spelling of 215664773 in words is "two hundred fifteen million, six hundred sixty-four thousand, seven hundred seventy-three".