216905669 has 8 divisors (see below), whose sum is σ = 230352408. Its totient is φ = 203535360.

The previous prime is 216905657. The next prime is 216905671. The reversal of 216905669 is 966509612.

It can be written as a sum of positive squares in 4 ways, for example, as 97812100 + 119093569 = 9890^2 + 10913^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-216905669 is a prime.

It is a super-2 number, since 2×216905669² = 94096138488675122, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (216905629) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 13202 + ... + 24659.

It is an arithmetic number, because the mean of its divisors is an integer number (28794051).

Almost surely, 2^216905669 is an apocalyptic number.

It is an amenable number.

216905669 is a deficient number, since it is larger than the sum of its proper divisors (13446739).

216905669 is a wasteful number, since it uses less digits than its factorization.

216905669 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 38215.

The product of its (nonzero) digits is 174960, while the sum is 44.

The square root of 216905669 is about 14727.7177118520. The cubic root of 216905669 is about 600.8374130958.

The spelling of 216905669 in words is "two hundred sixteen million, nine hundred five thousand, six hundred sixty-nine".