121787761 has 4 divisors (see below), whose sum is σ = 121925952. Its totient is φ = 121649572.

The previous prime is 121787717. The next prime is 121787789. The reversal of 121787761 is 167787121.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 167787121 = 1747 ⋅96043.

It is a cyclic number.

It is not a de Polignac number, because 121787761 - 2¹⁵ = 121754993 is a prime.

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (121787161) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 67765 + ... + 69538.

It is an arithmetic number, because the mean of its divisors is an integer number (30481488).

Almost surely, 2^121787761 is an apocalyptic number.

It is an amenable number.

121787761 is a deficient number, since it is larger than the sum of its proper divisors (138191).

121787761 is an equidigital number, since it uses as much as digits as its factorization.

121787761 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 138190.

The product of its digits is 32928, while the sum is 40.

The square root of 121787761 is about 11035.7492269442. The cubic root of 121787761 is about 495.6797938145.

The spelling of 121787761 in words is "one hundred twenty-one million, seven hundred eighty-seven thousand, seven hundred sixty-one".