155104021 has 2 divisors, whose sum is σ = 155104022. Its totient is φ = 155104020.

The previous prime is 155104003. The next prime is 155104043. The reversal of 155104021 is 120401551.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 112996900 + 42107121 = 10630^2 + 6489^2 .

It is a cyclic number.

It is not a de Polignac number, because 155104021 - 2⁵ = 155103989 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 155104021.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (155104051) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 77552010 + 77552011.

It is an arithmetic number, because the mean of its divisors is an integer number (77552011).

Almost surely, 2^155104021 is an apocalyptic number.

It is an amenable number.

155104021 is a deficient number, since it is larger than the sum of its proper divisors (1).

155104021 is an equidigital number, since it uses as much as digits as its factorization.

155104021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 200, while the sum is 19.

The square root of 155104021 is about 12454.0764812169. The cubic root of 155104021 is about 537.2886738024.

Adding to 155104021 its reverse (120401551), we get a palindrome (275505572).

The spelling of 155104021 in words is "one hundred fifty-five million, one hundred four thousand, twenty-one".