2157803909 has 2 divisors, whose sum is σ = 2157803910. Its totient is φ = 2157803908.

The previous prime is 2157803833. The next prime is 2157803917. The reversal of 2157803909 is 9093087512.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1739724100 + 418079809 = 41710^2 + 20447^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-2157803909 is a prime.

It is a super-2 number, since 2×2157803909² = 9312235419391360562, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 2157803909.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2157809909) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1078901954 + 1078901955.

It is an arithmetic number, because the mean of its divisors is an integer number (1078901955).

Almost surely, 2^2157803909 is an apocalyptic number.

It is an amenable number.

2157803909 is a deficient number, since it is larger than the sum of its proper divisors (1).

2157803909 is an equidigital number, since it uses as much as digits as its factorization.

2157803909 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 136080, while the sum is 44.

The square root of 2157803909 is about 46452.1679687827. The cubic root of 2157803909 is about 1292.2225789263. Note that the first 3 decimals are identical.

The spelling of 2157803909 in words is "two billion, one hundred fifty-seven million, eight hundred three thousand, nine hundred nine".