15665981423 has 4 divisors (see below), whose sum is σ = 16587509760. Its totient is φ = 14744453088.

The previous prime is 15665981417. The next prime is 15665981447. The reversal of 15665981423 is 32418956651.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 32418956651 = 499 ⋅64967849.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-15665981423 is a prime.

It is a super-2 number, since 2×15665981423² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (15665984423) 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, 460764143 + ... + 460764176.

It is an arithmetic number, because the mean of its divisors is an integer number (4146877440).

Almost surely, 2^15665981423 is an apocalyptic number.

15665981423 is a deficient number, since it is larger than the sum of its proper divisors (921528337).

15665981423 is an equidigital number, since it uses as much as digits as its factorization.

15665981423 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 921528336.

The product of its digits is 1555200, while the sum is 50.

The spelling of 15665981423 in words is "fifteen billion, six hundred sixty-five million, nine hundred eighty-one thousand, four hundred twenty-three".