155489689 has 2 divisors, whose sum is σ = 155489690. Its totient is φ = 155489688.

The previous prime is 155489687. The next prime is 155489693. The reversal of 155489689 is 986984551.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 132641289 + 22848400 = 11517^2 + 4780^2 .

It is a cyclic number.

It is not a de Polignac number, because 155489689 - 2¹ = 155489687 is a prime.

Together with 155489687, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (155489681) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 77744844 + 77744845.

It is an arithmetic number, because the mean of its divisors is an integer number (77744845).

Almost surely, 2^155489689 is an apocalyptic number.

It is an amenable number.

155489689 is a deficient number, since it is larger than the sum of its proper divisors (1).

155489689 is an equidigital number, since it uses as much as digits as its factorization.

155489689 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3110400, while the sum is 55.

The square root of 155489689 is about 12469.5504730523. The cubic root of 155489689 is about 537.7336301102.

The spelling of 155489689 in words is "one hundred fifty-five million, four hundred eighty-nine thousand, six hundred eighty-nine".