1263721 has 4 divisors (see below), whose sum is σ = 1285200. Its totient is φ = 1242244.

The previous prime is 1263701. The next prime is 1263751. The reversal of 1263721 is 1273621.

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: 1273621 = 107 ⋅11903.

It is a cyclic number.

It is not a de Polignac number, because 1263721 - 2⁹ = 1263209 is a prime.

It is a Duffinian number.

1263721 is a lucky number.

It is a junction number, because it is equal to n+sod(n) for n = 1263692 and 1263701.

It is not an unprimeable number, because it can be changed into a prime (1263701) 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, 10651 + ... + 10768.

It is an arithmetic number, because the mean of its divisors is an integer number (321300).

2^1263721 is an apocalyptic number.

It is an amenable number.

1263721 is a deficient number, since it is larger than the sum of its proper divisors (21479).

1263721 is an equidigital number, since it uses as much as digits as its factorization.

1263721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21478.

The product of its digits is 504, while the sum is 22.

The square root of 1263721 is about 1124.1534592750. The cubic root of 1263721 is about 108.1144477211.

The spelling of 1263721 in words is "one million, two hundred sixty-three thousand, seven hundred twenty-one".