215623813 has 2 divisors, whose sum is σ = 215623814. Its totient is φ = 215623812.

The previous prime is 215623777. The next prime is 215623841. The reversal of 215623813 is 318326512.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 207878724 + 7745089 = 14418^2 + 2783^2 .

It is a cyclic number.

It is not a de Polignac number, because 215623813 - 2¹⁷ = 215492741 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (215623843) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 107811906 + 107811907.

It is an arithmetic number, because the mean of its divisors is an integer number (107811907).

Almost surely, 2^215623813 is an apocalyptic number.

It is an amenable number.

215623813 is a deficient number, since it is larger than the sum of its proper divisors (1).

215623813 is an equidigital number, since it uses as much as digits as its factorization.

215623813 is an evil number, because the sum of its binary digits is even.

The product of its digits is 8640, while the sum is 31.

The square root of 215623813 is about 14684.1347378727. The cubic root of 215623813 is about 599.6514762949.

The spelling of 215623813 in words is "two hundred fifteen million, six hundred twenty-three thousand, eight hundred thirteen".