155220205430521 has 16 divisors (see below), whose sum is σ = 193537357430400. Its totient is φ = 120940770458880.

The previous prime is 155220205430491. The next prime is 155220205430557. The reversal of 155220205430521 is 125034502022551.

It is a cyclic number.

It is not a de Polignac number, because 155220205430521 - 2¹⁷ = 155220205299449 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (155220205430921) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 82724266 + ... + 84579811.

It is an arithmetic number, because the mean of its divisors is an integer number (12096084839400).

Almost surely, 2^{155220205430521} is an apocalyptic number.

155220205430521 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

155220205430521 is a deficient number, since it is larger than the sum of its proper divisors (38317151999879).

155220205430521 is a wasteful number, since it uses less digits than its factorization.

155220205430521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 167316144.

The product of its (nonzero) digits is 120000, while the sum is 37.

The spelling of 155220205430521 in words is "one hundred fifty-five trillion, two hundred twenty billion, two hundred five million, four hundred thirty thousand, five hundred twenty-one".