15218476981 has 2 divisors, whose sum is σ = 15218476982. Its totient is φ = 15218476980.

The previous prime is 15218476979. The next prime is 15218476991. The reversal of 15218476981 is 18967481251.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 13974786225 + 1243690756 = 118215^2 + 35266^2 .

It is an emirp because it is prime and its reverse (18967481251) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 15218476981 - 2¹ = 15218476979 is a prime.

It is a super-2 number, since 2×15218476981² (a number of 21 digits) contains 22 as substring.

Together with 15218476979, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (15218476991) 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, 7609238490 + 7609238491.

It is an arithmetic number, because the mean of its divisors is an integer number (7609238491).

Almost surely, 2^15218476981 is an apocalyptic number.

It is an amenable number.

15218476981 is a deficient number, since it is larger than the sum of its proper divisors (1).

15218476981 is an equidigital number, since it uses as much as digits as its factorization.

15218476981 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 967680, while the sum is 52.

The spelling of 15218476981 in words is "fifteen billion, two hundred eighteen million, four hundred seventy-six thousand, nine hundred eighty-one".