7421921 has 8 divisors (see below), whose sum is σ = 8022504. Its totient is φ = 6825600.

The previous prime is 7421891. The next prime is 7421923. The reversal of 7421921 is 1291247.

It can be written as a sum of positive squares in 4 ways, for example, as 583696 + 6838225 = 764^2 + 2615^2 .

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 7421921 - 2⁶ = 7421857 is a prime.

It is a super-2 number, since 2×7421921² = 110169822660482, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (7421923) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3221 + ... + 5021.

It is an arithmetic number, because the mean of its divisors is an integer number (1002813).

Almost surely, 2^7421921 is an apocalyptic number.

It is an amenable number.

7421921 is a deficient number, since it is larger than the sum of its proper divisors (600583).

7421921 is a wasteful number, since it uses less digits than its factorization.

7421921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2131.

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

The square root of 7421921 is about 2724.3202821988. The cubic root of 7421921 is about 195.0617468275.

The spelling of 7421921 in words is "seven million, four hundred twenty-one thousand, nine hundred twenty-one".