155421603634553 has 2 divisors, whose sum is σ = 155421603634554. Its totient is φ = 155421603634552.

The previous prime is 155421603634463. The next prime is 155421603634613. The reversal of 155421603634553 is 355436306124551.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 149117019977104 + 6304583657449 = 12211348^2 + 2510893^2 .

It is an emirp because it is prime and its reverse (355436306124551) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 155421603634553 - 2¹⁶ = 155421603569017 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 155421603634495 and 155421603634504.

It is not a weakly prime, because it can be changed into another prime (155421603034553) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 77710801817276 + 77710801817277.

It is an arithmetic number, because the mean of its divisors is an integer number (77710801817277).

Almost surely, 2^{155421603634553} is an apocalyptic number.

It is an amenable number.

155421603634553 is a deficient number, since it is larger than the sum of its proper divisors (1).

155421603634553 is an equidigital number, since it uses as much as digits as its factorization.

155421603634553 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 19440000, while the sum is 53.

The spelling of 155421603634553 in words is "one hundred fifty-five trillion, four hundred twenty-one billion, six hundred three million, six hundred thirty-four thousand, five hundred fifty-three".