121780811 has 2 divisors, whose sum is σ = 121780812. Its totient is φ = 121780810.

The previous prime is 121780793. The next prime is 121780871. The reversal of 121780811 is 118087121.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 121780811 - 2¹⁴ = 121764427 is a prime.

It is not a weakly prime, because it can be changed into another prime (121780871) 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 as a sum of consecutive naturals, namely, 60890405 + 60890406.

It is an arithmetic number, because the mean of its divisors is an integer number (60890406).

Almost surely, 2^121780811 is an apocalyptic number.

121780811 is a deficient number, since it is larger than the sum of its proper divisors (1).

121780811 is an equidigital number, since it uses as much as digits as its factorization.

121780811 is an odious number, because the sum of its binary digits is odd.

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

The square root of 121780811 is about 11035.4343367173. The cubic root of 121780811 is about 495.6703647332.

It can be divided in two parts, 1217 and 80811, that added together give a palindrome (82028).

The spelling of 121780811 in words is "one hundred twenty-one million, seven hundred eighty thousand, eight hundred eleven".