12261991 has 8 divisors (see below), whose sum is σ = 14034944. Its totient is φ = 10494360.

The previous prime is 12261961. The next prime is 12262021. The reversal of 12261991 is 19916221.

It is an interprime number because it is at equal distance from previous prime (12261961) and next prime (12262021).

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 12261991 - 2¹³ = 12253799 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (12261901) 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, 7906 + ... + 9328.

It is an arithmetic number, because the mean of its divisors is an integer number (1754368).

Almost surely, 2^12261991 is an apocalyptic number.

12261991 is a deficient number, since it is larger than the sum of its proper divisors (1772953).

12261991 is a wasteful number, since it uses less digits than its factorization.

12261991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2661.

The product of its digits is 1944, while the sum is 31.

The square root of 12261991 is about 3501.7125810095. The cubic root of 12261991 is about 230.5970060493.

The spelling of 12261991 in words is "twelve million, two hundred sixty-one thousand, nine hundred ninety-one".