1421721 has 12 divisors (see below), whose sum is σ = 2347072. Its totient is φ = 812376.

The previous prime is 1421711. The next prime is 1421731. The reversal of 1421721 is 1271241.

It is an interprime number because it is at equal distance from previous prime (1421711) and next prime (1421731).

It is not a de Polignac number, because 1421721 - 2⁵ = 1421689 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 1421694 and 1421703.

It is not an unprimeable number, because it can be changed into a prime (1421711) 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 11 ways as a sum of consecutive naturals, for example, 11221 + ... + 11346.

2^1421721 is an apocalyptic number.

It is an amenable number.

1421721 is a deficient number, since it is larger than the sum of its proper divisors (925351).

1421721 is a wasteful number, since it uses less digits than its factorization.

1421721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22580 (or 22577 counting only the distinct ones).

The product of its digits is 112, while the sum is 18.

The square root of 1421721 is about 1192.3594256767. The cubic root of 1421721 is about 112.4444763048. Note that the first 4 decimals are identical.

Adding to 1421721 its reverse (1271241), we get a palindrome (2692962).

The spelling of 1421721 in words is "one million, four hundred twenty-one thousand, seven hundred twenty-one".