161751203640 has 320 divisors, whose sum is σ = 589778703360. Its totient is φ = 39523645440.

The previous prime is 161751203609. The next prime is 161751203683. The reversal of 161751203640 is 46302157161.

161751203640 is a `hidden beast` number, since 1 + 6 + 1 + 7 + 5 + 1 + 2 + 0 + 3 + 640 = 666.

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

It is a junction number, because it is equal to n+sod(n) for n = 161751203595 and 161751203604.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 5756425 + ... + 5784455.

It is an arithmetic number, because the mean of its divisors is an integer number (1843058448).

Almost surely, 2^161751203640 is an apocalyptic number.

161751203640 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 161751203640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (294889351680).

161751203640 is an abundant number, since it is smaller than the sum of its proper divisors (428027499720).

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

161751203640 is a wasteful number, since it uses less digits than its factorization.

161751203640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 28204 (or 28191 counting only the distinct ones).

The product of its (nonzero) digits is 30240, while the sum is 36.

The spelling of 161751203640 in words is "one hundred sixty-one billion, seven hundred fifty-one million, two hundred three thousand, six hundred forty".