121554781 has 2 divisors, whose sum is σ = 121554782. Its totient is φ = 121554780.

The previous prime is 121554749. The next prime is 121554821. The reversal of 121554781 is 187455121.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 95452900 + 26101881 = 9770^2 + 5109^2 .

It is a cyclic number.

It is not a de Polignac number, because 121554781 - 2⁵ = 121554749 is a prime.

It is a super-2 number, since 2×121554781² = 29551129567915922, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (121554721) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 60777390 + 60777391.

It is an arithmetic number, because the mean of its divisors is an integer number (60777391).

Almost surely, 2^121554781 is an apocalyptic number.

It is an amenable number.

121554781 is a deficient number, since it is larger than the sum of its proper divisors (1).

121554781 is an equidigital number, since it uses as much as digits as its factorization.

121554781 is an evil number, because the sum of its binary digits is even.

The product of its digits is 11200, while the sum is 34.

The square root of 121554781 is about 11025.1884791145. The cubic root of 121554781 is about 495.3635135475.

The spelling of 121554781 in words is "one hundred twenty-one million, five hundred fifty-four thousand, seven hundred eighty-one".