15661277 has 2 divisors, whose sum is σ = 15661278. Its totient is φ = 15661276.

The previous prime is 15661273. The next prime is 15661279. The reversal of 15661277 is 77216651.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 10329796 + 5331481 = 3214^2 + 2309^2 .

It is an emirp because it is prime and its reverse (77216651) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 15661277 - 2² = 15661273 is a prime.

Together with 15661279, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (15661273) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 7830638 + 7830639.

It is an arithmetic number, because the mean of its divisors is an integer number (7830639).

Almost surely, 2^15661277 is an apocalyptic number.

It is an amenable number.

15661277 is a deficient number, since it is larger than the sum of its proper divisors (1).

15661277 is an equidigital number, since it uses as much as digits as its factorization.

15661277 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 17640, while the sum is 35.

The square root of 15661277 is about 3957.4331327263. The cubic root of 15661277 is about 250.1933277923.

The spelling of 15661277 in words is "fifteen million, six hundred sixty-one thousand, two hundred seventy-seven".