1243721 has 8 divisors (see below), whose sum is σ = 1330080. Its totient is φ = 1159488.

The previous prime is 1243717. The next prime is 1243741. The reversal of 1243721 is 1273421.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 1243721 - 2² = 1243717 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1243693 and 1243702.

It is not an unprimeable number, because it can be changed into a prime (1243741) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 785 + ... + 1761.

It is an arithmetic number, because the mean of its divisors is an integer number (166260).

2^1243721 is an apocalyptic number.

It is an amenable number.

1243721 is a deficient number, since it is larger than the sum of its proper divisors (86359).

1243721 is an equidigital number, since it uses as much as digits as its factorization.

1243721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1063.

The product of its digits is 336, while the sum is 20.

The square root of 1243721 is about 1115.2223993446. Note that the first 3 decimals coincide. The cubic root of 1243721 is about 107.5410623734.

The spelling of 1243721 in words is "one million, two hundred forty-three thousand, seven hundred twenty-one".