7289921 has 2 divisors, whose sum is σ = 7289922. Its totient is φ = 7289920.

The previous prime is 7289917. The next prime is 7289959. The reversal of 7289921 is 1299827.

It is an a-pointer prime, because the next prime (7289959) can be obtained adding 7289921 to its sum of digits (38).

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 7263025 + 26896 = 2695^2 + 164^2 .

It is an emirp because it is prime and its reverse (1299827) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 7289921 - 2² = 7289917 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (7289911) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3644960 + 3644961.

It is an arithmetic number, because the mean of its divisors is an integer number (3644961).

Almost surely, 2^7289921 is an apocalyptic number.

It is an amenable number.

7289921 is a deficient number, since it is larger than the sum of its proper divisors (1).

7289921 is an equidigital number, since it uses as much as digits as its factorization.

7289921 is an evil number, because the sum of its binary digits is even.

The product of its digits is 18144, while the sum is 38.

The square root of 7289921 is about 2699.9853703307. The cubic root of 7289921 is about 193.8984216874.

The spelling of 7289921 in words is "seven million, two hundred eighty-nine thousand, nine hundred twenty-one".