215545540 has 48 divisors (see below), whose sum is σ = 523152000. Its totient is φ = 73066752.

The previous prime is 215545531. The next prime is 215545591. The reversal of 215545540 is 45545512.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3811 + ... + 21109.

It is an arithmetic number, because the mean of its divisors is an integer number (10899000).

Almost surely, 2^215545540 is an apocalyptic number.

215545540 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 215545540, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (261576000).

215545540 is an abundant number, since it is smaller than the sum of its proper divisors (307606460).

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

215545540 is a wasteful number, since it uses less digits than its factorization.

215545540 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17404 (or 17402 counting only the distinct ones).

The product of its (nonzero) digits is 20000, while the sum is 31.

The square root of 215545540 is about 14681.4692725217. The cubic root of 215545540 is about 599.5789082424.

The spelling of 215545540 in words is "two hundred fifteen million, five hundred forty-five thousand, five hundred forty".