155776121 has 2 divisors, whose sum is σ = 155776122. Its totient is φ = 155776120.

The previous prime is 155776109. The next prime is 155776123. The reversal of 155776121 is 121677551.

155776121 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 113720896 + 42055225 = 10664^2 + 6485^2 .

It is a cyclic number.

It is not a de Polignac number, because 155776121 - 2²² = 151581817 is a prime.

Together with 155776123, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (155776123) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 77888060 + 77888061.

It is an arithmetic number, because the mean of its divisors is an integer number (77888061).

Almost surely, 2^155776121 is an apocalyptic number.

It is an amenable number.

155776121 is a deficient number, since it is larger than the sum of its proper divisors (1).

155776121 is an equidigital number, since it uses as much as digits as its factorization.

155776121 is an evil number, because the sum of its binary digits is even.

The product of its digits is 14700, while the sum is 35.

The square root of 155776121 is about 12481.0304462412. The cubic root of 155776121 is about 538.0636190619.

The spelling of 155776121 in words is "one hundred fifty-five million, seven hundred seventy-six thousand, one hundred twenty-one".