2148123809 has 4 divisors (see below), whose sum is σ = 2313364116. Its totient is φ = 1982883504.

The previous prime is 2148123797. The next prime is 2148123821. The reversal of 2148123809 is 9083218412.

It is a semiprime because it is the product of two primes.

It is an interprime number because it is at equal distance from previous prime (2148123797) and next prime (2148123821).

It can be written as a sum of positive squares in 2 ways, for example, as 1246443025 + 901680784 = 35305^2 + 30028^2 .

It is a cyclic number.

It is not a de Polignac number, because 2148123809 - 2¹² = 2148119713 is a prime.

It is a super-2 number, since 2×2148123809² = 9228871797585336962, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (2148123899) 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, 82620134 + ... + 82620159.

It is an arithmetic number, because the mean of its divisors is an integer number (578341029).

Almost surely, 2^2148123809 is an apocalyptic number.

It is an amenable number.

2148123809 is a deficient number, since it is larger than the sum of its proper divisors (165240307).

2148123809 is a wasteful number, since it uses less digits than its factorization.

2148123809 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 165240306.

The product of its (nonzero) digits is 27648, while the sum is 38.

The square root of 2148123809 is about 46347.8565739560. The cubic root of 2148123809 is about 1290.2873403945.

The spelling of 2148123809 in words is "two billion, one hundred forty-eight million, one hundred twenty-three thousand, eight hundred nine".