121988165 has 8 divisors (see below), whose sum is σ = 157646328. Its totient is φ = 90083520.

The previous prime is 121988129. The next prime is 121988177. The reversal of 121988165 is 561889121.

It can be written as a sum of positive squares in 4 ways, for example, as 12952801 + 109035364 = 3599^2 + 10442^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 121988165 - 2⁶ = 121988101 is a prime.

It is a super-2 number, since 2×121988165² = 29762224800134450, which contains 22 as substring.

It is a Duffinian number.

It is a nialpdrome in base 15.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 938306 + ... + 938435.

It is an arithmetic number, because the mean of its divisors is an integer number (19705791).

Almost surely, 2^121988165 is an apocalyptic number.

It is an amenable number.

121988165 is a deficient number, since it is larger than the sum of its proper divisors (35658163).

121988165 is a wasteful number, since it uses less digits than its factorization.

121988165 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1876759.

The product of its digits is 34560, while the sum is 41.

The square root of 121988165 is about 11044.8252589165. The cubic root of 121988165 is about 495.9515282259.

The spelling of 121988165 in words is "one hundred twenty-one million, nine hundred eighty-eight thousand, one hundred sixty-five".