215405985 has 16 divisors (see below), whose sum is σ = 345502080. Its totient is φ = 114599040.

The previous prime is 215405969. The next prime is 215405989. The reversal of 215405985 is 589504512.

It is not a de Polignac number, because 215405985 - 2⁴ = 215405969 is a prime.

It is not an unprimeable number, because it can be changed into a prime (215405989) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 11421 + ... + 23690.

It is an arithmetic number, because the mean of its divisors is an integer number (21593880).

Almost surely, 2^215405985 is an apocalyptic number.

It is an amenable number.

215405985 is a deficient number, since it is larger than the sum of its proper divisors (130096095).

215405985 is a wasteful number, since it uses less digits than its factorization.

215405985 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 35528.

The product of its (nonzero) digits is 72000, while the sum is 39.

The square root of 215405985 is about 14676.7157429719. The cubic root of 215405985 is about 599.4494811473.

The spelling of 215405985 in words is "two hundred fifteen million, four hundred five thousand, nine hundred eighty-five".