655501661521 has 24 divisors (see below), whose sum is σ = 767286560040. Its totient is φ = 558352569600.

The previous prime is 655501661491. The next prime is 655501661537. The reversal of 655501661521 is 125166105556.

655501661521 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 4 ways, for example, as 136397262400 + 519104399121 = 369320^2 + 720489^2 .

It is not a de Polignac number, because 655501661521 - 2⁵ = 655501661489 is a prime.

It is not an unprimeable number, because it can be changed into a prime (655501161521) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 12647941 + ... + 12699661.

It is an arithmetic number, because the mean of its divisors is an integer number (31970273335).

Almost surely, 2^655501661521 is an apocalyptic number.

It is an amenable number.

655501661521 is a deficient number, since it is larger than the sum of its proper divisors (111784898519).

655501661521 is a wasteful number, since it uses less digits than its factorization.

655501661521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 53345 (or 53338 counting only the distinct ones).

The product of its (nonzero) digits is 270000, while the sum is 43.

The spelling of 655501661521 in words is "six hundred fifty-five billion, five hundred one million, six hundred sixty-one thousand, five hundred twenty-one".