216871949 has 4 divisors (see below), whose sum is σ = 247853664. Its totient is φ = 185890236.

The previous prime is 216871937. The next prime is 216871951. The reversal of 216871949 is 949178612.

216871949 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 216871949 - 2⁴ = 216871933 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (216871049) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 15490847 + ... + 15490860.

It is an arithmetic number, because the mean of its divisors is an integer number (61963416).

Almost surely, 2^216871949 is an apocalyptic number.

It is an amenable number.

216871949 is a deficient number, since it is larger than the sum of its proper divisors (30981715).

216871949 is an equidigital number, since it uses as much as digits as its factorization.

216871949 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 30981714.

The product of its digits is 217728, while the sum is 47.

The square root of 216871949 is about 14726.5728871316. The cubic root of 216871949 is about 600.8062762309.

The spelling of 216871949 in words is "two hundred sixteen million, eight hundred seventy-one thousand, nine hundred forty-nine".