12511721 has 2 divisors, whose sum is σ = 12511722. Its totient is φ = 12511720.

The previous prime is 12511703. The next prime is 12511757. The reversal of 12511721 is 12711521.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 8185321 + 4326400 = 2861^2 + 2080^2 .

It is a cyclic number.

It is not a de Polignac number, because 12511721 - 2²² = 8317417 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 12511693 and 12511702.

It is not a weakly prime, because it can be changed into another prime (12511621) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6255860 + 6255861.

It is an arithmetic number, because the mean of its divisors is an integer number (6255861).

Almost surely, 2^12511721 is an apocalyptic number.

It is an amenable number.

12511721 is a deficient number, since it is larger than the sum of its proper divisors (1).

12511721 is an equidigital number, since it uses as much as digits as its factorization.

12511721 is an evil number, because the sum of its binary digits is even.

The product of its digits is 140, while the sum is 20.

The square root of 12511721 is about 3537.1911172567. The cubic root of 12511721 is about 232.1519577700.

The spelling of 12511721 in words is "twelve million, five hundred eleven thousand, seven hundred twenty-one".