161749770 has 128 divisors (see below), whose sum is σ = 481904640. Its totient is φ = 33834240.

The previous prime is 161749769. The next prime is 161749807. The reversal of 161749770 is 77947161.

It is a Harshad number since it is a multiple of its sum of digits (42).

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, 488505 + ... + 488835.

It is an arithmetic number, because the mean of its divisors is an integer number (3764880).

Almost surely, 2^161749770 is an apocalyptic number.

161749770 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 161749770, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (240952320).

161749770 is an abundant number, since it is smaller than the sum of its proper divisors (320154870).

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

161749770 is a wasteful number, since it uses less digits than its factorization.

161749770 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 540.

The product of its (nonzero) digits is 74088, while the sum is 42.

The square root of 161749770 is about 12718.0882997406. The cubic root of 161749770 is about 544.8553553802.

The spelling of 161749770 in words is "one hundred sixty-one million, seven hundred forty-nine thousand, seven hundred seventy".