161515505601 has 32 divisors (see below), whose sum is σ = 252694149120. Its totient is φ = 101754454032.

The previous prime is 161515505537. The next prime is 161515505603. The reversal of 161515505601 is 106505515161.

It is a happy number.

161515505601 is a `hidden beast` number, since 1 + 6 + 1 + 51 + 550 + 56 + 0 + 1 = 666.

It is not a de Polignac number, because 161515505601 - 2⁶ = 161515505537 is a prime.

It is not an unprimeable number, because it can be changed into a prime (161515505603) 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 31 ways as a sum of consecutive naturals, for example, 1515261 + ... + 1618346.

It is an arithmetic number, because the mean of its divisors is an integer number (7896692160).

Almost surely, 2^161515505601 is an apocalyptic number.

It is an amenable number.

161515505601 is a deficient number, since it is larger than the sum of its proper divisors (91178643519).

161515505601 is a wasteful number, since it uses less digits than its factorization.

161515505601 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3133722 (or 3133716 counting only the distinct ones).

The product of its (nonzero) digits is 22500, while the sum is 36.

The spelling of 161515505601 in words is "one hundred sixty-one billion, five hundred fifteen million, five hundred five thousand, six hundred one".