121801817 has 8 divisors (see below), whose sum is σ = 125243592. Its totient is φ = 118368000.

The previous prime is 121801807. The next prime is 121801819. The reversal of 121801817 is 718108121.

It can be written as a sum of positive squares in 4 ways, for example, as 2468041 + 119333776 = 1571^2 + 10924^2 .

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

It is a cyclic number.

It is not a de Polignac number, because 121801817 - 2¹⁰ = 121800793 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 121801817.

It is not an unprimeable number, because it can be changed into a prime (121801819) 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, 43067 + ... + 45807.

It is an arithmetic number, because the mean of its divisors is an integer number (15655449).

Almost surely, 2^121801817 is an apocalyptic number.

It is an amenable number.

121801817 is a deficient number, since it is larger than the sum of its proper divisors (3441775).

121801817 is a wasteful number, since it uses less digits than its factorization.

121801817 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3979.

The product of its (nonzero) digits is 896, while the sum is 29.

The square root of 121801817 is about 11036.3860479778. The cubic root of 121801817 is about 495.6988625263.

Adding to 121801817 its reverse (718108121), we get a palindrome (839909938).

The spelling of 121801817 in words is "one hundred twenty-one million, eight hundred one thousand, eight hundred seventeen".