155223535021 has 4 divisors (see below), whose sum is σ = 155224890844. Its totient is φ = 155222179200.

The previous prime is 155223534997. The next prime is 155223535057. The reversal of 155223535021 is 120535322551.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 120535322551 = 7 ⋅17219331793.

It can be written as a sum of positive squares in 2 ways, for example, as 54994940100 + 100228594921 = 234510^2 + 316589^2 .

It is a cyclic number.

It is not a de Polignac number, because 155223535021 - 2⁵ = 155223534989 is a prime.

It is a super-2 number, since 2×155223535021² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (155223535091) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 488550 + ... + 741031.

It is an arithmetic number, because the mean of its divisors is an integer number (38806222711).

Almost surely, 2^155223535021 is an apocalyptic number.

It is an amenable number.

155223535021 is a deficient number, since it is larger than the sum of its proper divisors (1355823).

155223535021 is a wasteful number, since it uses less digits than its factorization.

155223535021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1355822.

The product of its (nonzero) digits is 45000, while the sum is 34.

Adding to 155223535021 its reverse (120535322551), we get a palindrome (275758857572).

The spelling of 155223535021 in words is "one hundred fifty-five billion, two hundred twenty-three million, five hundred thirty-five thousand, twenty-one".