156798749981 has 2 divisors, whose sum is σ = 156798749982. Its totient is φ = 156798749980.

The previous prime is 156798749959. The next prime is 156798750007. The reversal of 156798749981 is 189947897651.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 119767905625 + 37030844356 = 346075^2 + 192434^2 .

It is an emirp because it is prime and its reverse (189947897651) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 156798749981 - 2⁶ = 156798749917 is a prime.

It is a super-2 number, since 2×156798749981² (a number of 23 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 156798749899 and 156798749908.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (156798749581) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 78399374990 + 78399374991.

It is an arithmetic number, because the mean of its divisors is an integer number (78399374991).

Almost surely, 2^156798749981 is an apocalyptic number.

It is an amenable number.

156798749981 is a deficient number, since it is larger than the sum of its proper divisors (1).

156798749981 is an equidigital number, since it uses as much as digits as its factorization.

156798749981 is an evil number, because the sum of its binary digits is even.

The product of its digits is 274337280, while the sum is 74.

The spelling of 156798749981 in words is "one hundred fifty-six billion, seven hundred ninety-eight million, seven hundred forty-nine thousand, nine hundred eighty-one".