7421621 has 4 divisors (see below), whose sum is σ = 7505100. Its totient is φ = 7338144.

The previous prime is 7421587. The next prime is 7421633. The reversal of 7421621 is 1261247.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 2515396 + 4906225 = 1586^2 + 2215^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-7421621 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (7421641) 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, 41606 + ... + 41783.

It is an arithmetic number, because the mean of its divisors is an integer number (1876275).

Almost surely, 2^7421621 is an apocalyptic number.

It is an amenable number.

7421621 is a deficient number, since it is larger than the sum of its proper divisors (83479).

7421621 is an equidigital number, since it uses as much as digits as its factorization.

7421621 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 83478.

The product of its digits is 672, while the sum is 23.

The square root of 7421621 is about 2724.2652220369. The cubic root of 7421621 is about 195.0591186080.

Adding to 7421621 its reverse (1261247), we get a palindrome (8682868).

The spelling of 7421621 in words is "seven million, four hundred twenty-one thousand, six hundred twenty-one".