121531665 has 8 divisors (see below), whose sum is σ = 194450688. Its totient is φ = 64816880.

The previous prime is 121531661. The next prime is 121531679. The reversal of 121531665 is 566135121.

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

It is not a de Polignac number, because 121531665 - 2² = 121531661 is a prime.

It is a super-3 number, since 3×121531665³ (a number of 25 digits) contains 333 as substring.

It is not an unprimeable number, because it can be changed into a prime (121531661) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4051041 + ... + 4051070.

It is an arithmetic number, because the mean of its divisors is an integer number (24306336).

Almost surely, 2^121531665 is an apocalyptic number.

121531665 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

121531665 is a deficient number, since it is larger than the sum of its proper divisors (72919023).

121531665 is an equidigital number, since it uses as much as digits as its factorization.

121531665 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8102119.

The product of its digits is 5400, while the sum is 30.

The square root of 121531665 is about 11024.1401025205. The cubic root of 121531665 is about 495.3321105624.

Adding to 121531665 its reverse (566135121), we get a palindrome (687666786).

The spelling of 121531665 in words is "one hundred twenty-one million, five hundred thirty-one thousand, six hundred sixty-five".