2155434320581 has 2 divisors, whose sum is σ = 2155434320582. Its totient is φ = 2155434320580.

The previous prime is 2155434320483. The next prime is 2155434320591. The reversal of 2155434320581 is 1850234345512.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1904217844356 + 251216476225 = 1379934^2 + 501215^2 .

It is a cyclic number.

It is not a de Polignac number, because 2155434320581 - 2⁷ = 2155434320453 is a prime.

It is a super-2 number, since 2×2155434320581² (a number of 25 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2155434320591) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1077717160290 + 1077717160291.

It is an arithmetic number, because the mean of its divisors is an integer number (1077717160291).

Almost surely, 2^{2155434320581} is an apocalyptic number.

It is an amenable number.

2155434320581 is a deficient number, since it is larger than the sum of its proper divisors (1).

2155434320581 is an equidigital number, since it uses as much as digits as its factorization.

2155434320581 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 576000, while the sum is 43.

The spelling of 2155434320581 in words is "two trillion, one hundred fifty-five billion, four hundred thirty-four million, three hundred twenty thousand, five hundred eighty-one".