15666231551 has 4 divisors (see below), whose sum is σ = 15724470600. Its totient is φ = 15607992504.

The previous prime is 15666231547. The next prime is 15666231571. The reversal of 15666231551 is 15513266651.

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

It is a cyclic number.

It is not a de Polignac number, because 15666231551 - 2² = 15666231547 is a prime.

It is a super-2 number, since 2×15666231551² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 15666231499 and 15666231508.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (15666231571) 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, 29119121 + ... + 29119658.

It is an arithmetic number, because the mean of its divisors is an integer number (3931117650).

Almost surely, 2^15666231551 is an apocalyptic number.

15666231551 is a deficient number, since it is larger than the sum of its proper divisors (58239049).

15666231551 is an equidigital number, since it uses as much as digits as its factorization.

15666231551 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 58239048.

The product of its digits is 162000, while the sum is 41.

The spelling of 15666231551 in words is "fifteen billion, six hundred sixty-six million, two hundred thirty-one thousand, five hundred fifty-one".