216391757 has 2 divisors, whose sum is σ = 216391758. Its totient is φ = 216391756.

The previous prime is 216391699. The next prime is 216391789. The reversal of 216391757 is 757193612.

216391757 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 213481321 + 2910436 = 14611^2 + 1706^2 .

It is a cyclic number.

It is not a de Polignac number, because 216391757 - 2¹⁴ = 216375373 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (216391157) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 108195878 + 108195879.

It is an arithmetic number, because the mean of its divisors is an integer number (108195879).

Almost surely, 2^216391757 is an apocalyptic number.

It is an amenable number.

216391757 is a deficient number, since it is larger than the sum of its proper divisors (1).

216391757 is an equidigital number, since it uses as much as digits as its factorization.

216391757 is an evil number, because the sum of its binary digits is even.

The product of its digits is 79380, while the sum is 41.

The square root of 216391757 is about 14710.2602628234. The cubic root of 216391757 is about 600.3625188856.

The spelling of 216391757 in words is "two hundred sixteen million, three hundred ninety-one thousand, seven hundred fifty-seven".