216478811 has 8 divisors (see below), whose sum is σ = 222762624. Its totient is φ = 210242880.

The previous prime is 216478789. The next prime is 216478853. The reversal of 216478811 is 118874612.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 216478811 - 2¹⁸ = 216216667 is a prime.

It is a super-2 number, since 2×216478811² = 93726151223947442, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (216478861) 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, 2696 + ... + 20981.

It is an arithmetic number, because the mean of its divisors is an integer number (27845328).

Almost surely, 2^216478811 is an apocalyptic number.

216478811 is a deficient number, since it is larger than the sum of its proper divisors (6283813).

216478811 is a wasteful number, since it uses less digits than its factorization.

216478811 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 23941.

The product of its digits is 21504, while the sum is 38.

The square root of 216478811 is about 14713.2189204130. The cubic root of 216478811 is about 600.4430163322.

The spelling of 216478811 in words is "two hundred sixteen million, four hundred seventy-eight thousand, eight hundred eleven".