5156521721 has 8 divisors (see below), whose sum is σ = 5557024704. Its totient is φ = 4756568400.

The previous prime is 5156521673. The next prime is 5156521729. The reversal of 5156521721 is 1271256515.

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

It is a cyclic number.

It is not a de Polignac number, because 5156521721 - 2¹⁰ = 5156520697 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (5156521729) 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, 117821 + ... + 155546.

It is an arithmetic number, because the mean of its divisors is an integer number (694628088).

Almost surely, 2^5156521721 is an apocalyptic number.

It is an amenable number.

5156521721 is a deficient number, since it is larger than the sum of its proper divisors (400502983).

5156521721 is a wasteful number, since it uses less digits than its factorization.

5156521721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 274831.

The product of its digits is 21000, while the sum is 35.

The square root of 5156521721 is about 71808.9250789900. The cubic root of 5156521721 is about 1727.6361537513.

The spelling of 5156521721 in words is "five billion, one hundred fifty-six million, five hundred twenty-one thousand, seven hundred twenty-one".