161533440 has 400 divisors, whose sum is σ = 623866320. Its totient is φ = 39813120.

The previous prime is 161533423. The next prime is 161533447. The reversal of 161533440 is 44335161.

161533440 is a `hidden beast` number, since 1 + 615 + 3 + 3 + 4 + 40 = 666.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (161533447) by changing a digit.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 3939820 + ... + 3939860.

Almost surely, 2^161533440 is an apocalyptic number.

161533440 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 161533440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (311933160).

161533440 is an abundant number, since it is smaller than the sum of its proper divisors (462332880).

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

161533440 is an equidigital number, since it uses as much as digits as its factorization.

161533440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 95 (or 70 counting only the distinct ones).

The product of its (nonzero) digits is 4320, while the sum is 27.

The square root of 161533440 is about 12709.5806382429. The cubic root of 161533440 is about 544.6123439160.

The spelling of 161533440 in words is "one hundred sixty-one million, five hundred thirty-three thousand, four hundred forty".