15155561 has 2 divisors, whose sum is σ = 15155562.
Its totient is φ = 15155560.
The previous prime is 15155557. The next prime is 15155563. The reversal of 15155561 is 16555151.
It is a happy number.
15155561 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.
It is a strong prime.
It can be written as a sum of positive squares in only one way, i.e., 9486400 + 5669161 = 3080^2 + 2381^2
It is an emirp because it is prime and its reverse (16555151) is a distict prime.
It is a cyclic number.
It is not a de Polignac number, because 15155561 - 22 = 15155557 is a prime.
Together with 15155563, it forms a pair of twin primes.
It is a Chen prime.
It is not a weakly prime, because it can be changed into another prime (15155563) by changing a digit.
It is a polite number, since it can be written as a sum of consecutive naturals, namely, 7577780 + 7577781.
It is an arithmetic number, because the mean of its divisors is an integer number (7577781).
Almost surely, 215155561 is an apocalyptic number.
It is an amenable number.
15155561 is a deficient number, since it is larger than the sum of its proper divisors (1).
15155561 is an equidigital number, since it uses as much as digits as its factorization.
15155561 is an evil number, because the sum of its binary digits is even.
The product of its digits is 3750, while the sum is 29.
The square root of 15155561 is about 3893.0143847666.
The cubic root of 15155561 is about 247.4708247077.
The spelling of 15155561 in words is "fifteen million, one hundred fifty-five thousand, five hundred sixty-one".