2155817099 has 4 divisors (see below), whose sum is σ = 2214082464. Its totient is φ = 2097551736.

The previous prime is 2155817077. The next prime is 2155817129. The reversal of 2155817099 is 9907185512.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 2155817099 - 2⁸ = 2155816843 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2155816099) 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, 29132627 + ... + 29132700.

It is an arithmetic number, because the mean of its divisors is an integer number (553520616).

Almost surely, 2^2155817099 is an apocalyptic number.

2155817099 is a deficient number, since it is larger than the sum of its proper divisors (58265365).

2155817099 is an equidigital number, since it uses as much as digits as its factorization.

2155817099 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 58265364.

The product of its (nonzero) digits is 226800, while the sum is 47.

The square root of 2155817099 is about 46430.7774972593. Note that the first 3 decimals coincide. The cubic root of 2155817099 is about 1291.8258500859.

The spelling of 2155817099 in words is "two billion, one hundred fifty-five million, eight hundred seventeen thousand, ninety-nine".