7681451721 has 16 divisors (see below), whose sum is σ = 10714975488. Its totient is φ = 4889763200.

The previous prime is 7681451699. The next prime is 7681451741. The reversal of 7681451721 is 1271541867.

It is a cyclic number.

It is not a de Polignac number, because 7681451721 - 2¹³ = 7681443529 is a prime.

It is not an unprimeable number, because it can be changed into a prime (7681451741) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 658590 + ... + 670151.

It is an arithmetic number, because the mean of its divisors is an integer number (669685968).

Almost surely, 2^7681451721 is an apocalyptic number.

It is an amenable number.

7681451721 is a deficient number, since it is larger than the sum of its proper divisors (3033523767).

7681451721 is a wasteful number, since it uses less digits than its factorization.

7681451721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1328832.

The product of its digits is 94080, while the sum is 42.

The square root of 7681451721 is about 87643.8915213148. The cubic root of 7681451721 is about 1973.0939659330.

The spelling of 7681451721 in words is "seven billion, six hundred eighty-one million, four hundred fifty-one thousand, seven hundred twenty-one".