7748721 has 6 divisors (see below), whose sum is σ = 11192610. Its totient is φ = 5165808.

The previous prime is 7748717. The next prime is 7748737. The reversal of 7748721 is 1278477.

It can be written as a sum of positive squares in only one way, i.e., 4562496 + 3186225 = 2136^2 + 1785^2 .

It is not a de Polignac number, because 7748721 - 2² = 7748717 is a prime.

It is not an unprimeable number, because it can be changed into a prime (7748711) 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 in 5 ways as a sum of consecutive naturals, for example, 430476 + ... + 430493.

It is an arithmetic number, because the mean of its divisors is an integer number (1865435).

Almost surely, 2^7748721 is an apocalyptic number.

It is an amenable number.

7748721 is a deficient number, since it is larger than the sum of its proper divisors (3443889).

7748721 is a wasteful number, since it uses less digits than its factorization.

7748721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 860975 (or 860972 counting only the distinct ones).

The product of its digits is 21952, while the sum is 36.

The square root of 7748721 is about 2783.6524567553. The cubic root of 7748721 is about 197.8836935553.

The spelling of 7748721 in words is "seven million, seven hundred forty-eight thousand, seven hundred twenty-one".