72128781635356 has 24 divisors (see below), whose sum is σ = 127790006079456. Its totient is φ = 35620102340160.

The previous prime is 72128781635321. The next prime is 72128781635357. The reversal of 72128781635356 is 65353618782127.

It is a happy number.

It is a super-2 number, since 2×72128781635356² (a number of 29 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (72128781635357) 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, 343771615 + ... + 343981366.

It is an arithmetic number, because the mean of its divisors is an integer number (5324583586644).

Almost surely, 2^{72128781635356} is an apocalyptic number.

It is an amenable number.

72128781635356 is a deficient number, since it is larger than the sum of its proper divisors (55661224444100).

72128781635356 is a wasteful number, since it uses less digits than its factorization.

72128781635356 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 687753309 (or 687753307 counting only the distinct ones).

The product of its digits is 101606400, while the sum is 64.

The spelling of 72128781635356 in words is "seventy-two trillion, one hundred twenty-eight billion, seven hundred eighty-one million, six hundred thirty-five thousand, three hundred fifty-six".