155021551321 has 48 divisors (see below), whose sum is σ = 195477722496. Its totient is φ = 121851765504.

The previous prime is 155021551319. The next prime is 155021551367. The reversal of 155021551321 is 123155120551.

It is not a de Polignac number, because 155021551321 - 2¹ = 155021551319 is a prime.

It is not an unprimeable number, because it can be changed into a prime (155021551021) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 93554725 + ... + 93556381.

It is an arithmetic number, because the mean of its divisors is an integer number (4072452552).

Almost surely, 2^155021551321 is an apocalyptic number.

It is an amenable number.

155021551321 is a deficient number, since it is larger than the sum of its proper divisors (40456171175).

155021551321 is a wasteful number, since it uses less digits than its factorization.

155021551321 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2558 (or 2551 counting only the distinct ones).

The product of its (nonzero) digits is 7500, while the sum is 31.

Adding to 155021551321 its reverse (123155120551), we get a palindrome (278176671872).

The spelling of 155021551321 in words is "one hundred fifty-five billion, twenty-one million, five hundred fifty-one thousand, three hundred twenty-one".