155440502149981 has 2 divisors, whose sum is σ = 155440502149982. Its totient is φ = 155440502149980.

The previous prime is 155440502149967. The next prime is 155440502150033. The reversal of 155440502149981 is 189941205044551.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 125048104965081 + 30392397184900 = 11182491^2 + 5512930^2 .

It is an emirp because it is prime and its reverse (189941205044551) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 155440502149981 - 2¹⁵ = 155440502117213 is a prime.

It is a super-2 number, since 2×155440502149981² (a number of 29 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (155440502149951) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 77720251074990 + 77720251074991.

It is an arithmetic number, because the mean of its divisors is an integer number (77720251074991).

Almost surely, 2^{155440502149981} is an apocalyptic number.

It is an amenable number.

155440502149981 is a deficient number, since it is larger than the sum of its proper divisors (1).

155440502149981 is an equidigital number, since it uses as much as digits as its factorization.

155440502149981 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 10368000, while the sum is 58.

The spelling of 155440502149981 in words is "one hundred fifty-five trillion, four hundred forty billion, five hundred two million, one hundred forty-nine thousand, nine hundred eighty-one".