12211720 has 32 divisors (see below), whose sum is σ = 27581400. Its totient is φ = 4866048.

The previous prime is 12211709. The next prime is 12211721. The reversal of 12211720 is 2711221.

It can be written as a sum of positive squares in 4 ways, for example, as 10074276 + 2137444 = 3174^2 + 1462^2 .

It is a super-2 number, since 2×12211720² = 298252210716800, which contains 22 as substring.

It is a plaindrome in base 15.

It is a junction number, because it is equal to n+sod(n) for n = 12211694 and 12211703.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (12211721) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 15496 + ... + 16264.

Almost surely, 2^12211720 is an apocalyptic number.

12211720 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

12211720 is an abundant number, since it is smaller than the sum of its proper divisors (15369680).

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

12211720 is a wasteful number, since it uses less digits than its factorization.

12211720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1177 (or 1173 counting only the distinct ones).

The product of its (nonzero) digits is 56, while the sum is 16.

The square root of 12211720 is about 3494.5271497014. The cubic root of 12211720 is about 230.2814450026.

Adding to 12211720 its reverse (2711221), we get a palindrome (14922941).

The spelling of 12211720 in words is "twelve million, two hundred eleven thousand, seven hundred twenty".