2180810261 has 4 divisors (see below), whose sum is σ = 2492354592. Its totient is φ = 1869265932.

The previous prime is 2180810257. The next prime is 2180810267. The reversal of 2180810261 is 1620180812.

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.

It is a cyclic number.

It is not a de Polignac number, because 2180810261 - 2² = 2180810257 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2180810267) 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, 155772155 + ... + 155772168.

It is an arithmetic number, because the mean of its divisors is an integer number (623088648).

Almost surely, 2^2180810261 is an apocalyptic number.

It is an amenable number.

2180810261 is a deficient number, since it is larger than the sum of its proper divisors (311544331).

2180810261 is an equidigital number, since it uses as much as digits as its factorization.

2180810261 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 311544330.

The product of its (nonzero) digits is 1536, while the sum is 29.

The square root of 2180810261 is about 46699.1462555794. The cubic root of 2180810261 is about 1296.7988816337.

The spelling of 2180810261 in words is "two billion, one hundred eighty million, eight hundred ten thousand, two hundred sixty-one".