12111571621 has 4 divisors (see below), whose sum is σ = 12150267052. Its totient is φ = 12072876192.

The previous prime is 12111571609. The next prime is 12111571643. The reversal of 12111571621 is 12617511121.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 25867396 + 12085704225 = 5086^2 + 109935^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-12111571621 is a prime.

It is a super-2 number, since 2×12111571621² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 12111571621.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (12111571921) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 19347246 + ... + 19347871.

It is an arithmetic number, because the mean of its divisors is an integer number (3037566763).

Almost surely, 2^12111571621 is an apocalyptic number.

It is an amenable number.

12111571621 is a deficient number, since it is larger than the sum of its proper divisors (38695431).

12111571621 is an equidigital number, since it uses as much as digits as its factorization.

12111571621 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 38695430.

The product of its digits is 840, while the sum is 28.

The spelling of 12111571621 in words is "twelve billion, one hundred eleven million, five hundred seventy-one thousand, six hundred twenty-one".