7421 has 4 divisors (see below), whose sum is σ = 7644. Its totient is φ = 7200.

The previous prime is 7417. The next prime is 7433. The reversal of 7421 is 1247.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1247 = 29 ⋅43.

It can be written as a sum of positive squares in 2 ways, for example, as 196 + 7225 = 14^2 + 85^2 .

It is a cyclic number.

It is not a de Polignac number, because 7421 - 2² = 7417 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a plaindrome in base 9 and base 13.

It is a nialpdrome in base 10.

It is a zygodrome in base 9.

It is a junction number, because it is equal to n+sod(n) for n = 7396 and 7405.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 7421.

It is not an unprimeable number, because it can be changed into a prime (7411) 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, 50 + ... + 131.

It is an arithmetic number, because the mean of its divisors is an integer number (1911).

2⁷⁴²¹ is an apocalyptic number.

It is an amenable number.

7421 is a deficient number, since it is larger than the sum of its proper divisors (223).

7421 is a wasteful number, since it uses less digits than its factorization.

7421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 222.

The product of its digits is 56, while the sum is 14.

The square root of 7421 is about 86.1452262171. The cubic root of 7421 is about 19.5053677969.

Adding to 7421 its reverse (1247), we get a palindrome (8668).

The spelling of 7421 in words is "seven thousand, four hundred twenty-one", and thus it is an iban number.