2159405681 has 4 divisors (see below), whose sum is σ = 2160270912. Its totient is φ = 2158540452.

The previous prime is 2159405653. The next prime is 2159405683. The reversal of 2159405681 is 1865049512.

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 2159405681 - 2⁶ = 2159405617 is a prime.

It is a super-3 number, since 3×2159405681³ (a number of 29 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2159405683) 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, 428861 + ... + 433866.

It is an arithmetic number, because the mean of its divisors is an integer number (540067728).

Almost surely, 2^2159405681 is an apocalyptic number.

It is an amenable number.

2159405681 is a deficient number, since it is larger than the sum of its proper divisors (865231).

2159405681 is an equidigital number, since it uses as much as digits as its factorization.

2159405681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 865230.

The product of its (nonzero) digits is 86400, while the sum is 41.

The square root of 2159405681 is about 46469.4058602001. The cubic root of 2159405681 is about 1292.5422456003.

The spelling of 2159405681 in words is "two billion, one hundred fifty-nine million, four hundred five thousand, six hundred eighty-one".