161665052400 has 90 divisors (see below), whose sum is σ = 561022651280. Its totient is φ = 43110679680.

The previous prime is 161665052389. The next prime is 161665052401. The reversal of 161665052400 is 4250566161.

It is a tau number, because it is divible by the number of its divisors (90).

It is a super-2 number, since 2×161665052400² (a number of 23 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (161665052401) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 22449880 + ... + 22457079.

Almost surely, 2^161665052400 is an apocalyptic number.

161665052400 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

161665052400 is an abundant number, since it is smaller than the sum of its proper divisors (399357598880).

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

161665052400 is a wasteful number, since it uses less digits than its factorization.

161665052400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 44906983 (or 44906969 counting only the distinct ones).

The product of its (nonzero) digits is 43200, while the sum is 36.

The spelling of 161665052400 in words is "one hundred sixty-one billion, six hundred sixty-five million, fifty-two thousand, four hundred".