161539686400 has 171 divisors, whose sum is σ = 403185615879. Its totient is φ = 64204308480.

The previous prime is 161539686397. The next prime is 161539686431. The reversal of 161539686400 is 4686935161.

The square root of 161539686400 is 401920.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in 4 ways, for example, as 19537330176 + 142002356224 = 139776^2 + 376832^2 .

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 1028915122 + ... + 1028915278.

Almost surely, 2^161539686400 is an apocalyptic number.

161539686400 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

161539686400 is the 401920-th square number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 161539686400

161539686400 is an abundant number, since it is smaller than the sum of its proper divisors (241645929479).

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

161539686400 is an frugal number, since it uses more digits than its factorization.

161539686400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 360 (or 164 counting only the distinct ones).

The product of its (nonzero) digits is 933120, while the sum is 49.

Multiplying 161539686400 by its sum of digits (49), we get a square (7915444633600 = 2813440²).

The spelling of 161539686400 in words is "one hundred sixty-one billion, five hundred thirty-nine million, six hundred eighty-six thousand, four hundred".