2154923509 has 4 divisors (see below), whose sum is σ = 2157581440. Its totient is φ = 2152265580.

The previous prime is 2154923489. The next prime is 2154923591. The reversal of 2154923509 is 9053294512.

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 2154923509 - 2¹³ = 2154915317 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 (2154953509) 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, 1327749 + ... + 1329370.

It is an arithmetic number, because the mean of its divisors is an integer number (539395360).

Almost surely, 2^2154923509 is an apocalyptic number.

It is an amenable number.

2154923509 is a deficient number, since it is larger than the sum of its proper divisors (2657931).

2154923509 is an equidigital number, since it uses as much as digits as its factorization.

2154923509 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2657930.

The product of its (nonzero) digits is 97200, while the sum is 40.

The square root of 2154923509 is about 46421.1536801920. The cubic root of 2154923509 is about 1291.6473373859.

The spelling of 2154923509 in words is "two billion, one hundred fifty-four million, nine hundred twenty-three thousand, five hundred nine".