7307721561 has 8 divisors (see below), whose sum is σ = 11135575744. Its totient is φ = 4175840880.

The previous prime is 7307721517. The next prime is 7307721563. The reversal of 7307721561 is 1651277037.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 7307721561 - 2¹¹ = 7307719513 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (7307721563) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 173993350 + ... + 173993391.

It is an arithmetic number, because the mean of its divisors is an integer number (1391946968).

Almost surely, 2^7307721561 is an apocalyptic number.

It is an amenable number.

7307721561 is a deficient number, since it is larger than the sum of its proper divisors (3827854183).

7307721561 is a wasteful number, since it uses less digits than its factorization.

7307721561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 347986751.

The product of its (nonzero) digits is 61740, while the sum is 39.

The square root of 7307721561 is about 85485.2125282496. The cubic root of 7307721561 is about 1940.5611407719.

Adding to 7307721561 its reverse (1651277037), we get a palindrome (8958998598).

The spelling of 7307721561 in words is "seven billion, three hundred seven million, seven hundred twenty-one thousand, five hundred sixty-one".