2157508809 has 6 divisors (see below), whose sum is σ = 3116401626. Its totient is φ = 1438339200.

The previous prime is 2157508799. The next prime is 2157508841. The reversal of 2157508809 is 9088057512.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 2134440000 + 23068809 = 46200^2 + 4803^2 .

It is not a de Polignac number, because 2157508809 - 2¹⁶ = 2157443273 is a prime.

It is not an unprimeable number, because it can be changed into a prime (2157508849) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 119861592 + ... + 119861609.

It is an arithmetic number, because the mean of its divisors is an integer number (519400271).

Almost surely, 2^2157508809 is an apocalyptic number.

It is an amenable number.

2157508809 is a deficient number, since it is larger than the sum of its proper divisors (958892817).

2157508809 is a wasteful number, since it uses less digits than its factorization.

2157508809 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 239723207 (or 239723204 counting only the distinct ones).

The product of its (nonzero) digits is 201600, while the sum is 45.

The square root of 2157508809 is about 46448.9914745197. The cubic root of 2157508809 is about 1292.1636683728.

The spelling of 2157508809 in words is "two billion, one hundred fifty-seven million, five hundred eight thousand, eight hundred nine".