155609945 has 4 divisors (see below), whose sum is σ = 186731940. Its totient is φ = 124487952.

The previous prime is 155609933. The next prime is 155609947. The reversal of 155609945 is 549906551.

155609945 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 549906551 = 31 ⋅17738921.

It can be written as a sum of positive squares in 2 ways, for example, as 30349081 + 125260864 = 5509^2 + 11192^2 .

It is a cyclic number.

It is not a de Polignac number, because 155609945 - 2¹⁶ = 155544409 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 155609896 and 155609905.

It is not an unprimeable number, because it can be changed into a prime (155609947) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 15560990 + ... + 15560999.

It is an arithmetic number, because the mean of its divisors is an integer number (46682985).

Almost surely, 2^155609945 is an apocalyptic number.

It is an amenable number.

155609945 is a deficient number, since it is larger than the sum of its proper divisors (31121995).

155609945 is an equidigital number, since it uses as much as digits as its factorization.

155609945 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 31121994.

The product of its (nonzero) digits is 243000, while the sum is 44.

The square root of 155609945 is about 12474.3715272554. The cubic root of 155609945 is about 537.8722224335.

The spelling of 155609945 in words is "one hundred fifty-five million, six hundred nine thousand, nine hundred forty-five".