7921421 has 4 divisors (see below), whose sum is σ = 7998432. Its totient is φ = 7844412.

The previous prime is 7921411. The next prime is 7921447. The reversal of 7921421 is 1241297.

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: 1241297 = 197 ⋅6301.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-7921421 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 (7921411) 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, 38351 + ... + 38556.

It is an arithmetic number, because the mean of its divisors is an integer number (1999608).

Almost surely, 2^7921421 is an apocalyptic number.

It is an amenable number.

7921421 is a deficient number, since it is larger than the sum of its proper divisors (77011).

7921421 is a wasteful number, since it uses less digits than its factorization.

7921421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 77010.

The product of its digits is 1008, while the sum is 26.

The square root of 7921421 is about 2814.5019097524. The cubic root of 7921421 is about 199.3430192445.

The spelling of 7921421 in words is "seven million, nine hundred twenty-one thousand, four hundred twenty-one".