15555555551 has 4 divisors (see below), whose sum is σ = 15564659400. Its totient is φ = 15546451704.

The previous prime is 15555555541. The next prime is 15555555581.

15555555551 is nontrivially palindromic in base 10.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-15555555551 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 15555555496 and 15555555505.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (15555555511) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4549361 + ... + 4552778.

It is an arithmetic number, because the mean of its divisors is an integer number (3891164850).

Almost surely, 2^15555555551 is an apocalyptic number.

15555555551 is a deficient number, since it is larger than the sum of its proper divisors (9103849).

15555555551 is an equidigital number, since it uses as much as digits as its factorization.

15555555551 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9103848.

The product of its digits is 1953125, while the sum is 47.

The spelling of 15555555551 in words is "fifteen billion, five hundred fifty-five million, five hundred fifty-five thousand, five hundred fifty-one".