215684740 has 12 divisors (see below), whose sum is σ = 452937996. Its totient is φ = 86273888.

The previous prime is 215684699. The next prime is 215684747. The reversal of 215684740 is 47486512.

215684740 is digitally balanced in base 3, 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 24581764 + 191102976 = 4958^2 + 13824^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 215684740.

It is not an unprimeable number, because it can be changed into a prime (215684747) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5392099 + ... + 5392138.

It is an arithmetic number, because the mean of its divisors is an integer number (37744833).

Almost surely, 2^215684740 is an apocalyptic number.

215684740 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

215684740 is an abundant number, since it is smaller than the sum of its proper divisors (237253256).

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

215684740 is a wasteful number, since it uses less digits than its factorization.

215684740 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10784246 (or 10784244 counting only the distinct ones).

The product of its (nonzero) digits is 53760, while the sum is 37.

The square root of 215684740 is about 14686.2091773201. The cubic root of 215684740 is about 599.7079504608.

The spelling of 215684740 in words is "two hundred fifteen million, six hundred eighty-four thousand, seven hundred forty".