161782790400 has 1944 divisors, whose sum is σ = 765141590304. Its totient is φ = 33443020800.

The previous prime is 161782790383. The next prime is 161782790401. The reversal of 161782790400 is 4097287161.

It is a happy number.

161782790400 is a `hidden beast` number, since 1 + 6 + 178 + 2 + 79 + 0 + 400 = 666.

It is a tau number, because it is divible by the number of its divisors (1944).

It is a super-2 number, since 2×161782790400² (a number of 23 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is not an unprimeable number, because it can be changed into a prime (161782790401) by changing a digit.

It is a polite number, since it can be written in 215 ways as a sum of consecutive naturals, for example, 838252704 + ... + 838252896.

Almost surely, 2^161782790400 is an apocalyptic number.

161782790400 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 161782790400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (382570795152).

161782790400 is an abundant number, since it is smaller than the sum of its proper divisors (603358799904).

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

161782790400 is a wasteful number, since it uses less digits than its factorization.

161782790400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 259 (or 221 counting only the distinct ones).

The product of its (nonzero) digits is 169344, while the sum is 45.

The spelling of 161782790400 in words is "one hundred sixty-one billion, seven hundred eighty-two million, seven hundred ninety thousand, four hundred".