1248491521 has 4 divisors (see below), whose sum is σ = 1249281792. Its totient is φ = 1247701252.

The previous prime is 1248491473. The next prime is 1248491537. The reversal of 1248491521 is 1251948421.

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 a de Polignac number, because none of the positive numbers 2^k-1248491521 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1248491921) 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, 392761 + ... + 395926.

It is an arithmetic number, because the mean of its divisors is an integer number (312320448).

Almost surely, 2^1248491521 is an apocalyptic number.

It is an amenable number.

1248491521 is a deficient number, since it is larger than the sum of its proper divisors (790271).

1248491521 is an equidigital number, since it uses as much as digits as its factorization.

1248491521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 790270.

The product of its digits is 23040, while the sum is 37.

The square root of 1248491521 is about 35333.9995047263. Note that the first 3 decimals coincide. The cubic root of 1248491521 is about 1076.7838479919.

The spelling of 1248491521 in words is "one billion, two hundred forty-eight million, four hundred ninety-one thousand, five hundred twenty-one".