2157864109 has 4 divisors (see below), whose sum is σ = 2190071104. Its totient is φ = 2125657116.

The previous prime is 2157864083. The next prime is 2157864127. The reversal of 2157864109 is 9014687512.

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 a de Polignac number, because none of the positive numbers 2^k-2157864109 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 (2157864169) 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, 16103397 + ... + 16103530.

It is an arithmetic number, because the mean of its divisors is an integer number (547517776).

Almost surely, 2^2157864109 is an apocalyptic number.

It is an amenable number.

2157864109 is a deficient number, since it is larger than the sum of its proper divisors (32206995).

2157864109 is an equidigital number, since it uses as much as digits as its factorization.

2157864109 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 32206994.

The product of its (nonzero) digits is 120960, while the sum is 43.

The square root of 2157864109 is about 46452.8159426315. The cubic root of 2157864109 is about 1292.2345959398.

The spelling of 2157864109 in words is "two billion, one hundred fifty-seven million, eight hundred sixty-four thousand, one hundred nine".