218540906 has 8 divisors (see below), whose sum is σ = 335806884. Its totient is φ = 106605280.

The previous prime is 218540887. The next prime is 218540977. The reversal of 218540906 is 609045812.

218540906 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 2 ways, for example, as 214358881 + 4182025 = 14641^2 + 2045^2 .

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

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1332485 + ... + 1332648.

Almost surely, 2^218540906 is an apocalyptic number.

218540906 is a deficient number, since it is larger than the sum of its proper divisors (117265978).

218540906 is a wasteful number, since it uses less digits than its factorization.

218540906 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2665176.

The product of its (nonzero) digits is 17280, while the sum is 35.

The square root of 218540906 is about 14783.1291004307. The cubic root of 218540906 is about 602.3435253051.

Subtracting from 218540906 its sum of digits (35), we obtain a triangular number (218540871 = T₂₀₉₀₆).

The spelling of 218540906 in words is "two hundred eighteen million, five hundred forty thousand, nine hundred six".