7640031721 has 4 divisors (see below), whose sum is σ = 8731464832. Its totient is φ = 6548598612.

The previous prime is 7640031703. The next prime is 7640031733. The reversal of 7640031721 is 1271300467.

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: 1271300467 = 1613 ⋅788159.

It is a cyclic number.

It is not a de Polignac number, because 7640031721 - 2⁹ = 7640031209 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (7640031781) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 545716545 + ... + 545716558.

It is an arithmetic number, because the mean of its divisors is an integer number (2182866208).

Almost surely, 2^7640031721 is an apocalyptic number.

It is an amenable number.

7640031721 is a deficient number, since it is larger than the sum of its proper divisors (1091433111).

7640031721 is a wasteful number, since it uses less digits than its factorization.

7640031721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1091433110.

The product of its (nonzero) digits is 7056, while the sum is 31.

The square root of 7640031721 is about 87407.2749889848. The cubic root of 7640031721 is about 1969.5411267712.

The spelling of 7640031721 in words is "seven billion, six hundred forty million, thirty-one thousand, seven hundred twenty-one".