121801665 has 32 divisors (see below), whose sum is σ = 199382400. Its totient is φ = 63475200.

The previous prime is 121801663. The next prime is 121801679. The reversal of 121801665 is 566108121.

It is not a de Polignac number, because 121801665 - 2¹ = 121801663 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (121801663) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 202365 + ... + 202965.

It is an arithmetic number, because the mean of its divisors is an integer number (6230700).

Almost surely, 2^121801665 is an apocalyptic number.

121801665 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

121801665 is a deficient number, since it is larger than the sum of its proper divisors (77580735).

121801665 is a wasteful number, since it uses less digits than its factorization.

121801665 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 897.

The product of its (nonzero) digits is 2880, while the sum is 30.

The square root of 121801665 is about 11036.3791616635. The cubic root of 121801665 is about 495.6986563273.

Adding to 121801665 its reverse (566108121), we get a palindrome (687909786).

The spelling of 121801665 in words is "one hundred twenty-one million, eight hundred one thousand, six hundred sixty-five".