155223215553421 has 2 divisors, whose sum is σ = 155223215553422. Its totient is φ = 155223215553420.

The previous prime is 155223215553401. The next prime is 155223215553443. The reversal of 155223215553421 is 124355512322551.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 144940867861321 + 10282347692100 = 12039139^2 + 3206610^2 .

It is an emirp because it is prime and its reverse (124355512322551) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 155223215553421 - 2⁷ = 155223215553293 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (155223215553401) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 77611607776710 + 77611607776711.

It is an arithmetic number, because the mean of its divisors is an integer number (77611607776711).

Almost surely, 2^{155223215553421} is an apocalyptic number.

It is an amenable number.

155223215553421 is a deficient number, since it is larger than the sum of its proper divisors (1).

155223215553421 is an equidigital number, since it uses as much as digits as its factorization.

155223215553421 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1800000, while the sum is 46.

Adding to 155223215553421 its reverse (124355512322551), we get a palindrome (279578727875972).

The spelling of 155223215553421 in words is "one hundred fifty-five trillion, two hundred twenty-three billion, two hundred fifteen million, five hundred fifty-three thousand, four hundred twenty-one".