211221513 has 10 divisors (see below), whose sum is σ = 315528554. Its totient is φ = 140814288.

The previous prime is 211221511. The next prime is 211221523. The reversal of 211221513 is 315122112.

211221513 is digitally balanced in base 2, 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 only one way, i.e., 138579984 + 72641529 = 11772^2 + 8523^2 .

It is not a de Polignac number, because 211221513 - 2¹ = 211221511 is a prime.

It is a super-2 number, since 2×211221513² = 89229055108018338, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (211221511) by changing a digit.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 1303756 + ... + 1303917.

Almost surely, 2^211221513 is an apocalyptic number.

It is an amenable number.

211221513 is a deficient number, since it is larger than the sum of its proper divisors (104307041).

211221513 is an equidigital number, since it uses as much as digits as its factorization.

211221513 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2607685 (or 2607676 counting only the distinct ones).

The product of its digits is 120, while the sum is 18.

The square root of 211221513 is about 14533.4618381169. The cubic root of 211221513 is about 595.5424406174.

Adding to 211221513 its reverse (315122112), we get a palindrome (526343625).

The spelling of 211221513 in words is "two hundred eleven million, two hundred twenty-one thousand, five hundred thirteen".