2209405981 has 4 divisors (see below), whose sum is σ = 2246853600. Its totient is φ = 2171958364.

The previous prime is 2209405963. The next prime is 2209405997. The reversal of 2209405981 is 1895049022.

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 2209405981 - 2⁵ = 2209405949 is a prime.

It is a super-2 number, since 2×2209405981² = 9762949577757144722, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2209405931) 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, 18723721 + ... + 18723838.

It is an arithmetic number, because the mean of its divisors is an integer number (561713400).

Almost surely, 2^2209405981 is an apocalyptic number.

It is an amenable number.

2209405981 is a deficient number, since it is larger than the sum of its proper divisors (37447619).

2209405981 is an equidigital number, since it uses as much as digits as its factorization.

2209405981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 37447618.

The product of its (nonzero) digits is 51840, while the sum is 40.

The square root of 2209405981 is about 47004.3187483874. The cubic root of 2209405981 is about 1302.4423476704.

The spelling of 2209405981 in words is "two billion, two hundred nine million, four hundred five thousand, nine hundred eighty-one".