161585505520 has 40 divisors (see below), whose sum is σ = 378207712800. Its totient is φ = 64200410880.

The previous prime is 161585505517. The next prime is 161585505541. The reversal of 161585505520 is 25505585161.

It is a tau number, because it is divible by the number of its divisors (40).

It is a super-2 number, since 2×161585505520² (a number of 23 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6765996 + ... + 6789835.

It is an arithmetic number, because the mean of its divisors is an integer number (9455192820).

Almost surely, 2^161585505520 is an apocalyptic number.

161585505520 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

161585505520 is an abundant number, since it is smaller than the sum of its proper divisors (216622207280).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

161585505520 is a wasteful number, since it uses less digits than its factorization.

161585505520 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13555993 (or 13555987 counting only the distinct ones).

The product of its (nonzero) digits is 300000, while the sum is 43.

The spelling of 161585505520 in words is "one hundred sixty-one billion, five hundred eighty-five million, five hundred five thousand, five hundred twenty".