7721501 has 2 divisors, whose sum is σ = 7721502. Its totient is φ = 7721500.

The previous prime is 7721479. The next prime is 7721521. The reversal of 7721501 is 1051277.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 5885476 + 1836025 = 2426^2 + 1355^2 .

It is an emirp because it is prime and its reverse (1051277) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 7721501 - 2⁶ = 7721437 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (7721521) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3860750 + 3860751.

It is an arithmetic number, because the mean of its divisors is an integer number (3860751).

Almost surely, 2^7721501 is an apocalyptic number.

It is an amenable number.

7721501 is a deficient number, since it is larger than the sum of its proper divisors (1).

7721501 is an equidigital number, since it uses as much as digits as its factorization.

7721501 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 490, while the sum is 23.

The square root of 7721501 is about 2778.7588956223. The cubic root of 7721501 is about 197.6517105974.

Adding to 7721501 its reverse (1051277), we get a palindrome (8772778).

The spelling of 7721501 in words is "seven million, seven hundred twenty-one thousand, five hundred one".