155019989 has 2 divisors, whose sum is σ = 155019990. Its totient is φ = 155019988.

The previous prime is 155019983. The next prime is 155020037. The reversal of 155019989 is 989910551.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 121727089 + 33292900 = 11033^2 + 5770^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-155019989 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (155019983) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 77509994 + 77509995.

It is an arithmetic number, because the mean of its divisors is an integer number (77509995).

Almost surely, 2^155019989 is an apocalyptic number.

It is an amenable number.

155019989 is a deficient number, since it is larger than the sum of its proper divisors (1).

155019989 is an equidigital number, since it uses as much as digits as its factorization.

155019989 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 145800, while the sum is 47.

The square root of 155019989 is about 12450.7023496669. The cubic root of 155019989 is about 537.1916258177.

The spelling of 155019989 in words is "one hundred fifty-five million, nineteen thousand, nine hundred eighty-nine".