155720516655657 has 4 divisors (see below), whose sum is σ = 207627355540880. Its totient is φ = 103813677770436.

The previous prime is 155720516655601. The next prime is 155720516655679. The reversal of 155720516655657 is 756556615027551.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 155720516655657 - 2⁶ = 155720516655593 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (155720516654657) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 25953419442607 + ... + 25953419442612.

It is an arithmetic number, because the mean of its divisors is an integer number (51906838885220).

Almost surely, 2^{155720516655657} is an apocalyptic number.

It is an amenable number.

155720516655657 is a deficient number, since it is larger than the sum of its proper divisors (51906838885223).

155720516655657 is an equidigital number, since it uses as much as digits as its factorization.

155720516655657 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 51906838885222.

The product of its (nonzero) digits is 330750000, while the sum is 66.

The spelling of 155720516655657 in words is "one hundred fifty-five trillion, seven hundred twenty billion, five hundred sixteen million, six hundred fifty-five thousand, six hundred fifty-seven".