1249932991 has 4 divisors (see below), whose sum is σ = 1250006032. Its totient is φ = 1249859952.

The previous prime is 1249932949. The next prime is 1249932997. The reversal of 1249932991 is 1992399421.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 1992399421 = 37 ⋅53848633.

It is a cyclic number.

It is not a de Polignac number, because 1249932991 - 2⁷ = 1249932863 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 (1249932997) 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, 4531 + ... + 50203.

It is an arithmetic number, because the mean of its divisors is an integer number (312501508).

Almost surely, 2^1249932991 is an apocalyptic number.

1249932991 is a deficient number, since it is larger than the sum of its proper divisors (73041).

1249932991 is an equidigital number, since it uses as much as digits as its factorization.

1249932991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 73040.

The product of its digits is 314928, while the sum is 49.

The square root of 1249932991 is about 35354.3913962608. The cubic root of 1249932991 is about 1077.1980958034.

The spelling of 1249932991 in words is "one billion, two hundred forty-nine million, nine hundred thirty-two thousand, nine hundred ninety-one".