15966374981 has 2 divisors, whose sum is σ = 15966374982. Its totient is φ = 15966374980.

The previous prime is 15966374969. The next prime is 15966374989. The reversal of 15966374981 is 18947366951.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 14716116100 + 1250258881 = 121310^2 + 35359^2 .

It is an emirp because it is prime and its reverse (18947366951) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 15966374981 - 2⁶ = 15966374917 is a prime.

It is a super-2 number, since 2×15966374981² (a number of 21 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 15966374981.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (15966374989) 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, 7983187490 + 7983187491.

It is an arithmetic number, because the mean of its divisors is an integer number (7983187491).

Almost surely, 2^15966374981 is an apocalyptic number.

It is an amenable number.

15966374981 is a deficient number, since it is larger than the sum of its proper divisors (1).

15966374981 is an equidigital number, since it uses as much as digits as its factorization.

15966374981 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 9797760, while the sum is 59.

The spelling of 15966374981 in words is "fifteen billion, nine hundred sixty-six million, three hundred seventy-four thousand, nine hundred eighty-one".