7620721 has 4 divisors (see below), whose sum is σ = 7782912. Its totient is φ = 7458532.

The previous prime is 7620703. The next prime is 7620733. The reversal of 7620721 is 1270267.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 1270267 = 23 ⋅55229.

It is a cyclic number.

It is not a de Polignac number, because 7620721 - 2⁷ = 7620593 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (7620421) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 81025 + ... + 81118.

It is an arithmetic number, because the mean of its divisors is an integer number (1945728).

Almost surely, 2^7620721 is an apocalyptic number.

It is an amenable number.

7620721 is a deficient number, since it is larger than the sum of its proper divisors (162191).

7620721 is a wasteful number, since it uses less digits than its factorization.

7620721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 162190.

The product of its (nonzero) digits is 1176, while the sum is 25.

The square root of 7620721 is about 2760.5653406504. The cubic root of 7620721 is about 196.7880341861.

Adding to 7620721 its reverse (1270267), we get a palindrome (8890988).

The spelling of 7620721 in words is "seven million, six hundred twenty thousand, seven hundred twenty-one".