161556036640 has 24 divisors (see below), whose sum is σ = 381676136940. Its totient is φ = 64622414592.

The previous prime is 161556036613. The next prime is 161556036667. The reversal of 161556036640 is 46630655161.

161556036640 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (161556036613) and next prime (161556036667).

It can be written as a sum of positive squares in 2 ways, for example, as 156192524944 + 5363511696 = 395212^2 + 73236^2 .

It is a super-2 number, since 2×161556036640² (a number of 23 digits) contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 504862455 + ... + 504862774.

Almost surely, 2^161556036640 is an apocalyptic number.

161556036640 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

161556036640 is an abundant number, since it is smaller than the sum of its proper divisors (220120100300).

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

161556036640 is a wasteful number, since it uses less digits than its factorization.

161556036640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1009725244 (or 1009725236 counting only the distinct ones).

The product of its (nonzero) digits is 388800, while the sum is 43.

The spelling of 161556036640 in words is "one hundred sixty-one billion, five hundred fifty-six million, thirty-six thousand, six hundred forty".