161709240 has 384 divisors, whose sum is σ = 640442880. Its totient is φ = 31933440.

The previous prime is 161709217. The next prime is 161709241. The reversal of 161709240 is 42907161.

161709240 = T₁₄₄ + T₁₄₅ + ... + T₉₉₀.

It is a happy number.

It is a super-2 number, since 2×161709240² = 52299756602755200, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a junction number, because it is equal to n+sod(n) for n = 161709198 and 161709207.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (161709241) by changing a digit.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 3760659 + ... + 3760701.

It is an arithmetic number, because the mean of its divisors is an integer number (1667820).

Almost surely, 2^161709240 is an apocalyptic number.

161709240 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 161709240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (320221440).

161709240 is an abundant number, since it is smaller than the sum of its proper divisors (478733640).

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

161709240 is a wasteful number, since it uses less digits than its factorization.

161709240 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 123 (or 108 counting only the distinct ones).

The product of its (nonzero) digits is 3024, while the sum is 30.

The square root of 161709240 is about 12716.4948000618. The cubic root of 161709240 is about 544.8098430388.

The spelling of 161709240 in words is "one hundred sixty-one million, seven hundred nine thousand, two hundred forty".