2000155561 has 2 divisors, whose sum is σ = 2000155562. Its totient is φ = 2000155560.

The previous prime is 2000155501. The next prime is 2000155571. The reversal of 2000155561 is 1655510002.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1810928025 + 189227536 = 42555^2 + 13756^2 .

It is a cyclic number.

It is not a de Polignac number, because 2000155561 - 2²¹ = 1998058409 is a prime.

It is not a weakly prime, because it can be changed into another prime (2000155501) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1000077780 + 1000077781.

It is an arithmetic number, because the mean of its divisors is an integer number (1000077781).

Almost surely, 2^2000155561 is an apocalyptic number.

It is an amenable number.

2000155561 is a deficient number, since it is larger than the sum of its proper divisors (1).

2000155561 is an equidigital number, since it uses as much as digits as its factorization.

2000155561 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1500, while the sum is 25.

The square root of 2000155561 is about 44723.0987410309. The cubic root of 2000155561 is about 1259.9537148111.

Adding to 2000155561 its reverse (1655510002), we get a palindrome (3655665563).

The spelling of 2000155561 in words is "two billion, one hundred fifty-five thousand, five hundred sixty-one".