15540001 has 2 divisors, whose sum is σ = 15540002. Its totient is φ = 15540000.

The previous prime is 15539999. The next prime is 15540013. The reversal of 15540001 is 10004551.

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., 14861025 + 678976 = 3855^2 + 824^2 .

It is a cyclic number.

It is not a de Polignac number, because 15540001 - 2¹ = 15539999 is a prime.

Together with 15539999, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (15543001) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 7770000 + 7770001.

It is an arithmetic number, because the mean of its divisors is an integer number (7770001).

Almost surely, 2^15540001 is an apocalyptic number.

It is an amenable number.

15540001 is a deficient number, since it is larger than the sum of its proper divisors (1).

15540001 is an equidigital number, since it uses as much as digits as its factorization.

15540001 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 100, while the sum is 16.

The square root of 15540001 is about 3942.0807957220. The cubic root of 15540001 is about 249.5458474815.

Adding to 15540001 its reverse (10004551), we get a palindrome (25544552).

The spelling of 15540001 in words is "fifteen million, five hundred forty thousand, one".