12437721 has 6 divisors (see below), whose sum is σ = 17965610. Its totient is φ = 8291808.

The previous prime is 12437701. The next prime is 12437743. The reversal of 12437721 is 12773421.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 11696400 + 741321 = 3420^2 + 861^2 .

It is not a de Polignac number, because 12437721 - 2⁹ = 12437209 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (12437701) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 690976 + ... + 690993.

Almost surely, 2^12437721 is an apocalyptic number.

It is an amenable number.

12437721 is a deficient number, since it is larger than the sum of its proper divisors (5527889).

12437721 is a wasteful number, since it uses less digits than its factorization.

12437721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1381975 (or 1381972 counting only the distinct ones).

The product of its digits is 2352, while the sum is 27.

The square root of 12437721 is about 3526.7153273265. The cubic root of 12437721 is about 231.6933684409.

The spelling of 12437721 in words is "twelve million, four hundred thirty-seven thousand, seven hundred twenty-one".