5181608721 has 8 divisors (see below), whose sum is σ = 7315212384. Its totient is φ = 3251205440.

The previous prime is 5181608713. The next prime is 5181608737. The reversal of 5181608721 is 1278061815.

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 5181608721 - 2³ = 5181608713 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 5181608721.

It is not an unprimeable number, because it can be changed into a prime (5181608701) 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, 50800035 + ... + 50800136.

It is an arithmetic number, because the mean of its divisors is an integer number (914401548).

Almost surely, 2^5181608721 is an apocalyptic number.

5181608721 is a gapful number since it is divisible by the number (51) formed by its first and last digit.

It is an amenable number.

5181608721 is a deficient number, since it is larger than the sum of its proper divisors (2133603663).

5181608721 is a wasteful number, since it uses less digits than its factorization.

5181608721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 101600191.

The product of its (nonzero) digits is 26880, while the sum is 39.

The square root of 5181608721 is about 71983.3919803728. The cubic root of 5181608721 is about 1730.4333307009.

The spelling of 5181608721 in words is "five billion, one hundred eighty-one million, six hundred eight thousand, seven hundred twenty-one".