2158556509 has 4 divisors (see below), whose sum is σ = 2252406816. Its totient is φ = 2064706204.

The previous prime is 2158556489. The next prime is 2158556531. The reversal of 2158556509 is 9056558512.

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 not a de Polignac number, because 2158556509 - 2¹³ = 2158548317 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 (2158556549) 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, 46925119 + ... + 46925164.

It is an arithmetic number, because the mean of its divisors is an integer number (563101704).

Almost surely, 2^2158556509 is an apocalyptic number.

It is an amenable number.

2158556509 is a deficient number, since it is larger than the sum of its proper divisors (93850307).

2158556509 is an equidigital number, since it uses as much as digits as its factorization.

2158556509 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 93850306.

The product of its (nonzero) digits is 540000, while the sum is 46.

The square root of 2158556509 is about 46460.2680685336. The cubic root of 2158556509 is about 1292.3727954906.

The spelling of 2158556509 in words is "two billion, one hundred fifty-eight million, five hundred fifty-six thousand, five hundred nine".