1264391249 has 4 divisors (see below), whose sum is σ = 1379335920. Its totient is φ = 1149446580.

The previous prime is 1264391231. The next prime is 1264391257. The reversal of 1264391249 is 9421934621.

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, and also an emirpimes, since its reverse is a distinct semiprime: 9421934621 = 11 ⋅856539511.

It is a cyclic number.

It is not a de Polignac number, because 1264391249 - 2⁸ = 1264390993 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1264391209) 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, 57472319 + ... + 57472340.

It is an arithmetic number, because the mean of its divisors is an integer number (344833980).

Almost surely, 2^1264391249 is an apocalyptic number.

It is an amenable number.

1264391249 is a deficient number, since it is larger than the sum of its proper divisors (114944671).

1264391249 is a wasteful number, since it uses less digits than its factorization.

1264391249 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 114944670.

The product of its digits is 93312, while the sum is 41.

The square root of 1264391249 is about 35558.2796124897. The cubic root of 1264391249 is about 1081.3355816118.

The spelling of 1264391249 in words is "one billion, two hundred sixty-four million, three hundred ninety-one thousand, two hundred forty-nine".