72121647717 has 12 divisors (see below), whose sum is σ = 119057958240. Its totient is φ = 41212370088.

The previous prime is 72121647691. The next prime is 72121647757. The reversal of 72121647717 is 71774612127.

It is not a de Polignac number, because 72121647717 - 2¹² = 72121643621 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (72121647757) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 572393967 + ... + 572394092.

It is an arithmetic number, because the mean of its divisors is an integer number (9921496520).

Almost surely, 2^72121647717 is an apocalyptic number.

It is an amenable number.

72121647717 is a deficient number, since it is larger than the sum of its proper divisors (46936310523).

72121647717 is a wasteful number, since it uses less digits than its factorization.

72121647717 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1144788072 (or 1144788069 counting only the distinct ones).

The product of its digits is 230496, while the sum is 45.

The spelling of 72121647717 in words is "seventy-two billion, one hundred twenty-one million, six hundred forty-seven thousand, seven hundred seventeen".