5151515625721 has 4 divisors (see below), whose sum is σ = 5170666241700. Its totient is φ = 5132365009744.

The previous prime is 5151515625713. The next prime is 5151515625811. The reversal of 5151515625721 is 1275265151515.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 3049563690000 + 2101951935721 = 1746300^2 + 1449811^2 .

It is a cyclic number.

It is not a de Polignac number, because 5151515625721 - 2³ = 5151515625713 is a prime.

It is a super-2 number, since 2×5151515625721² (a number of 26 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (5151515620721) 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, 9575307586 + ... + 9575308123.

It is an arithmetic number, because the mean of its divisors is an integer number (1292666560425).

Almost surely, 2^{5151515625721} is an apocalyptic number.

It is an amenable number.

5151515625721 is a deficient number, since it is larger than the sum of its proper divisors (19150615979).

5151515625721 is a wasteful number, since it uses less digits than its factorization.

5151515625721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19150615978.

The product of its digits is 525000, while the sum is 46.

The spelling of 5151515625721 in words is "five trillion, one hundred fifty-one billion, five hundred fifteen million, six hundred twenty-five thousand, seven hundred twenty-one".