12171620 has 12 divisors (see below), whose sum is σ = 25560444. Its totient is φ = 4868640.

The previous prime is 12171617. The next prime is 12171659. The reversal of 12171620 is 2617121.

It can be written as a sum of positive squares in 2 ways, for example, as 4631104 + 7540516 = 2152^2 + 2746^2 .

It is a Harshad number since it is a multiple of its sum of digits (20), and also a Moran number because the ratio is a prime number: 608581 = 12171620 / (1 + 2 + 1 + 7 + 1 + 6 + 2 + 0).

It is a junction number, because it is equal to n+sod(n) for n = 12171592 and 12171601.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 304271 + ... + 304310.

It is an arithmetic number, because the mean of its divisors is an integer number (2130037).

Almost surely, 2^12171620 is an apocalyptic number.

12171620 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

12171620 is an abundant number, since it is smaller than the sum of its proper divisors (13388824).

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

12171620 is a wasteful number, since it uses less digits than its factorization.

12171620 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 608590 (or 608588 counting only the distinct ones).

The product of its (nonzero) digits is 168, while the sum is 20.

The square root of 12171620 is about 3488.7848887542. The cubic root of 12171620 is about 230.0291078473.

Adding to 12171620 its reverse (2617121), we get a palindrome (14788741).

The spelling of 12171620 in words is "twelve million, one hundred seventy-one thousand, six hundred twenty".