211216520 has 16 divisors (see below), whose sum is σ = 475237260. Its totient is φ = 84486592.

The previous prime is 211216507. The next prime is 211216531. The reversal of 211216520 is 25612112.

It can be written as a sum of positive squares in 2 ways, for example, as 201469636 + 9746884 = 14194^2 + 3122^2 .

It is a super-2 number, since 2×211216520² = 89224836641820800, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (20).

It is a junction number, because it is equal to n+sod(n) for n = 211216492 and 211216501.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2640167 + ... + 2640246.

Almost surely, 2^211216520 is an apocalyptic number.

211216520 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

211216520 is an abundant number, since it is smaller than the sum of its proper divisors (264020740).

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

211216520 is a wasteful number, since it uses less digits than its factorization.

211216520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5280424 (or 5280420 counting only the distinct ones).

The product of its (nonzero) digits is 240, while the sum is 20.

The square root of 211216520 is about 14533.2900610977. The cubic root of 211216520 is about 595.5377479659.

Adding to 211216520 its reverse (25612112), we get a palindrome (236828632).

The spelling of 211216520 in words is "two hundred eleven million, two hundred sixteen thousand, five hundred twenty".