2158156709 has 4 divisors (see below), whose sum is σ = 2158799916. Its totient is φ = 2157513504.

The previous prime is 2158156699. The next prime is 2158156733. The reversal of 2158156709 is 9076518512.

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

It can be written as a sum of positive squares in 2 ways, for example, as 2118024484 + 40132225 = 46022^2 + 6335^2 .

It is a cyclic number.

It is not a de Polignac number, because 2158156709 - 2⁸ = 2158156453 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 2158156709.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2158156909) 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, 316544 + ... + 323289.

It is an arithmetic number, because the mean of its divisors is an integer number (539699979).

Almost surely, 2^2158156709 is an apocalyptic number.

It is an amenable number.

2158156709 is a deficient number, since it is larger than the sum of its proper divisors (643207).

2158156709 is an equidigital number, since it uses as much as digits as its factorization.

2158156709 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 643206.

The product of its (nonzero) digits is 151200, while the sum is 44.

The square root of 2158156709 is about 46455.9652681978. The cubic root of 2158156709 is about 1292.2930010315.

The spelling of 2158156709 in words is "two billion, one hundred fifty-eight million, one hundred fifty-six thousand, seven hundred nine".