215118820 has 72 divisors (see below), whose sum is σ = 528365376. Its totient is φ = 73354176.

The previous prime is 215118767. The next prime is 215118821. The reversal of 215118820 is 28811512.

It is a super-2 number, since 2×215118820² = 92552213436384800, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (28).

It is not an unprimeable number, because it can be changed into a prime (215118821) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 221977 + ... + 222943.

It is an arithmetic number, because the mean of its divisors is an integer number (7338408).

Almost surely, 2^215118820 is an apocalyptic number.

215118820 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 215118820, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (264182688).

215118820 is an abundant number, since it is smaller than the sum of its proper divisors (313246556).

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

215118820 is a wasteful number, since it uses less digits than its factorization.

215118820 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1217 (or 1208 counting only the distinct ones).

The product of its (nonzero) digits is 1280, while the sum is 28.

The square root of 215118820 is about 14666.9294673425. The cubic root of 215118820 is about 599.1829805630.

The spelling of 215118820 in words is "two hundred fifteen million, one hundred eighteen thousand, eight hundred twenty".