1247991 has 16 divisors (see below), whose sum is σ = 1741824. Its totient is φ = 794144.

The previous prime is 1247969. The next prime is 1248001. The reversal of 1247991 is 1997421.

It is a cyclic number.

It is not a de Polignac number, because 1247991 - 2⁵ = 1247959 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1247951) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 7390 + ... + 7556.

It is an arithmetic number, because the mean of its divisors is an integer number (108864).

2^1247991 is an apocalyptic number.

1247991 is a deficient number, since it is larger than the sum of its proper divisors (493833).

1247991 is a wasteful number, since it uses less digits than its factorization.

1247991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 270.

The product of its digits is 4536, while the sum is 33.

The square root of 1247991 is about 1117.1351753481. The cubic root of 1247991 is about 107.6639934328.

The spelling of 1247991 in words is "one million, two hundred forty-seven thousand, nine hundred ninety-one".