1249791509 has 4 divisors (see below), whose sum is σ = 1252358304. Its totient is φ = 1247224716.

The previous prime is 1249791497. The next prime is 1249791527. The reversal of 1249791509 is 9051979421.

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 1249791509 - 2¹⁶ = 1249725973 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 (1249791559) 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, 1282667 + ... + 1283640.

It is an arithmetic number, because the mean of its divisors is an integer number (313089576).

Almost surely, 2^1249791509 is an apocalyptic number.

It is an amenable number.

1249791509 is a deficient number, since it is larger than the sum of its proper divisors (2566795).

1249791509 is an equidigital number, since it uses as much as digits as its factorization.

1249791509 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2566794.

The product of its (nonzero) digits is 204120, while the sum is 47.

The square root of 1249791509 is about 35352.3904283713. The cubic root of 1249791509 is about 1077.1574509868.

The spelling of 1249791509 in words is "one billion, two hundred forty-nine million, seven hundred ninety-one thousand, five hundred nine".