161631120 has 320 divisors, whose sum is σ = 617103360. Its totient is φ = 34197504.

The previous prime is 161631101. The next prime is 161631139. The reversal of 161631120 is 21136161.

It is an interprime number because it is at equal distance from previous prime (161631101) and next prime (161631139).

It is a super-2 number, since 2×161631120² = 52249237904908800, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 1816036 + ... + 1816124.

It is an arithmetic number, because the mean of its divisors is an integer number (1928448).

Almost surely, 2^161631120 is an apocalyptic number.

161631120 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 161631120, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (308551680).

161631120 is an abundant number, since it is smaller than the sum of its proper divisors (455472240).

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

161631120 is a wasteful number, since it uses less digits than its factorization.

161631120 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 182 (or 176 counting only the distinct ones).

The product of its (nonzero) digits is 216, while the sum is 21.

The square root of 161631120 is about 12713.4228278619. The cubic root of 161631120 is about 544.7220983099.

Adding to 161631120 its reverse (21136161), we get a palindrome (182767281).

The spelling of 161631120 in words is "one hundred sixty-one million, six hundred thirty-one thousand, one hundred twenty".