7451921 has 4 divisors (see below), whose sum is σ = 7459812. Its totient is φ = 7444032.

The previous prime is 7451909. The next prime is 7451957. The reversal of 7451921 is 1291547.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 1380625 + 6071296 = 1175^2 + 2464^2 .

It is a cyclic number.

It is not a de Polignac number, because 7451921 - 2¹⁰ = 7450897 is a prime.

It is a super-2 number, since 2×7451921² = 111062253180482, which contains 22 as substring.

It is an Ulam number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (7451981) 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 3 ways as a sum of consecutive naturals, for example, 2300 + ... + 4493.

It is an arithmetic number, because the mean of its divisors is an integer number (1864953).

Almost surely, 2^7451921 is an apocalyptic number.

It is an amenable number.

7451921 is a deficient number, since it is larger than the sum of its proper divisors (7891).

7451921 is a wasteful number, since it uses less digits than its factorization.

7451921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7890.

The product of its digits is 2520, while the sum is 29.

The square root of 7451921 is about 2729.8206900820. The cubic root of 7451921 is about 195.3242119185.

The spelling of 7451921 in words is "seven million, four hundred fifty-one thousand, nine hundred twenty-one".