2155030261 has 4 divisors (see below), whose sum is σ = 2155131232. Its totient is φ = 2154929292.

The previous prime is 2155030249. The next prime is 2155030309. The reversal of 2155030261 is 1620305512.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 2155030261 - 2⁹ = 2155029749 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2155030231) 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, 4521 + ... + 65806.

It is an arithmetic number, because the mean of its divisors is an integer number (538782808).

Almost surely, 2^2155030261 is an apocalyptic number.

It is an amenable number.

2155030261 is a deficient number, since it is larger than the sum of its proper divisors (100971).

2155030261 is an equidigital number, since it uses as much as digits as its factorization.

2155030261 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 100970.

The product of its (nonzero) digits is 1800, while the sum is 25.

The square root of 2155030261 is about 46422.3034865785. The cubic root of 2155030261 is about 1291.6686658552.

Adding to 2155030261 its reverse (1620305512), we get a palindrome (3775335773).

The spelling of 2155030261 in words is "two billion, one hundred fifty-five million, thirty thousand, two hundred sixty-one".