216491478 has 16 divisors (see below), whose sum is σ = 494837760. Its totient is φ = 61854696.

The previous prime is 216491449. The next prime is 216491519. The reversal of 216491478 is 874194612.

It is a Harshad number since it is a multiple of its sum of digits (42), and also a Moran number because the ratio is a prime number: 5154559 = 216491478 / (2 + 1 + 6 + 4 + 9 + 1 + 4 + 7 + 8).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2577238 + ... + 2577321.

It is an arithmetic number, because the mean of its divisors is an integer number (30927360).

Almost surely, 2^216491478 is an apocalyptic number.

216491478 is an abundant number, since it is smaller than the sum of its proper divisors (278346282).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

216491478 is a wasteful number, since it uses less digits than its factorization.

216491478 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5154571.

The product of its digits is 96768, while the sum is 42.

The square root of 216491478 is about 14713.6493773639. The cubic root of 216491478 is about 600.4547275067.

The spelling of 216491478 in words is "two hundred sixteen million, four hundred ninety-one thousand, four hundred seventy-eight".