15855551 has 2 divisors, whose sum is σ = 15855552. Its totient is φ = 15855550.

The previous prime is 15855491. The next prime is 15855563. The reversal of 15855551 is 15555851.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-15855551 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (15855571) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 7927775 + 7927776.

It is an arithmetic number, because the mean of its divisors is an integer number (7927776).

Almost surely, 2^15855551 is an apocalyptic number.

15855551 is a deficient number, since it is larger than the sum of its proper divisors (1).

15855551 is an equidigital number, since it uses as much as digits as its factorization.

15855551 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 25000, while the sum is 35.

The square root of 15855551 is about 3981.9029370390. The cubic root of 15855551 is about 251.2236067092.

The spelling of 15855551 in words is "fifteen million, eight hundred fifty-five thousand, five hundred fifty-one".