155720502661321 has 16 divisors (see below), whose sum is σ = 177687044236800. Its totient is φ = 135192575962368.

The previous prime is 155720502661247. The next prime is 155720502661337. The reversal of 155720502661321 is 123166205027551.

It is a cyclic number.

It is not a de Polignac number, because 155720502661321 - 2⁹ = 155720502660809 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (155720500661321) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 244510911 + ... + 245146948.

It is an arithmetic number, because the mean of its divisors is an integer number (11105440264800).

Almost surely, 2^{155720502661321} is an apocalyptic number.

It is an amenable number.

155720502661321 is a deficient number, since it is larger than the sum of its proper divisors (21966541575479).

155720502661321 is a wasteful number, since it uses less digits than its factorization.

155720502661321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 489659328.

The product of its (nonzero) digits is 756000, while the sum is 46.

Adding to 155720502661321 its reverse (123166205027551), we get a palindrome (278886707688872).

The spelling of 155720502661321 in words is "one hundred fifty-five trillion, seven hundred twenty billion, five hundred two million, six hundred sixty-one thousand, three hundred twenty-one".