155065921 has 2 divisors, whose sum is σ = 155065922. Its totient is φ = 155065920.

The previous prime is 155065919. The next prime is 155065979. The reversal of 155065921 is 129560551.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 106832896 + 48233025 = 10336^2 + 6945^2 .

It is an emirp because it is prime and its reverse (129560551) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 155065921 - 2¹ = 155065919 is a prime.

Together with 155065919, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (155065991) 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, 77532960 + 77532961.

It is an arithmetic number, because the mean of its divisors is an integer number (77532961).

Almost surely, 2^155065921 is an apocalyptic number.

It is an amenable number.

155065921 is a deficient number, since it is larger than the sum of its proper divisors (1).

155065921 is an equidigital number, since it uses as much as digits as its factorization.

155065921 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 13500, while the sum is 34.

The square root of 155065921 is about 12452.5467676295. The cubic root of 155065921 is about 537.2446767164.

The spelling of 155065921 in words is "one hundred fifty-five million, sixty-five thousand, nine hundred twenty-one".