218148640 has 24 divisors (see below), whose sum is σ = 515376540. Its totient is φ = 87259392.

The previous prime is 218148617. The next prime is 218148649. The reversal of 218148640 is 46841812.

It can be written as a sum of positive squares in 2 ways, for example, as 194993296 + 23155344 = 13964^2 + 4812^2 .

It is a junction number, because it is equal to n+sod(n) for n = 218148596 and 218148605.

It is not an unprimeable number, because it can be changed into a prime (218148649) 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, 681555 + ... + 681874.

Almost surely, 2^218148640 is an apocalyptic number.

218148640 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

218148640 is an abundant number, since it is smaller than the sum of its proper divisors (297227900).

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

218148640 is a wasteful number, since it uses less digits than its factorization.

218148640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1363444 (or 1363436 counting only the distinct ones).

The product of its (nonzero) digits is 12288, while the sum is 34.

The square root of 218148640 is about 14769.8557880570. The cubic root of 218148640 is about 601.9829209696.

The spelling of 218148640 in words is "two hundred eighteen million, one hundred forty-eight thousand, six hundred forty".