1979487509 has 4 divisors (see below), whose sum is σ = 1980338316. Its totient is φ = 1978636704.

The previous prime is 1979487449. The next prime is 1979487527. The reversal of 1979487509 is 9057849791.

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 547092100 + 1432395409 = 23390^2 + 37847^2 .

It is a cyclic number.

It is not a de Polignac number, because 1979487509 - 2¹² = 1979483413 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1979487529) 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, 421904 + ... + 426569.

It is an arithmetic number, because the mean of its divisors is an integer number (495084579).

Almost surely, 2^1979487509 is an apocalyptic number.

It is an amenable number.

1979487509 is a deficient number, since it is larger than the sum of its proper divisors (850807).

1979487509 is an equidigital number, since it uses as much as digits as its factorization.

1979487509 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 850806.

The product of its (nonzero) digits is 5715360, while the sum is 59.

The square root of 1979487509 is about 44491.4318605279. The cubic root of 1979487509 is about 1255.5988864540.

The spelling of 1979487509 in words is "one billion, nine hundred seventy-nine million, four hundred eighty-seven thousand, five hundred nine".