216879749 has 2 divisors, whose sum is σ = 216879750. Its totient is φ = 216879748.

The previous prime is 216879721. The next prime is 216879757. The reversal of 216879749 is 947978612.

216879749 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., 202492900 + 14386849 = 14230^2 + 3793^2 .

It is a cyclic number.

It is not a de Polignac number, because 216879749 - 2⁸ = 216879493 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 216879749.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (216879779) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 108439874 + 108439875.

It is an arithmetic number, because the mean of its divisors is an integer number (108439875).

Almost surely, 2^216879749 is an apocalyptic number.

It is an amenable number.

216879749 is a deficient number, since it is larger than the sum of its proper divisors (1).

216879749 is an equidigital number, since it uses as much as digits as its factorization.

216879749 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1524096, while the sum is 53.

The square root of 216879749 is about 14726.8377121499. The cubic root of 216879749 is about 600.8134789955.

The spelling of 216879749 in words is "two hundred sixteen million, eight hundred seventy-nine thousand, seven hundred forty-nine".