67721012775 has 72 divisors (see below), whose sum is σ = 130978623776. Its totient is φ = 33249657600.

The previous prime is 67721012771. The next prime is 67721012819. The reversal of 67721012775 is 57721012776.

It is not a de Polignac number, because 67721012775 - 2² = 67721012771 is a prime.

It is a super-2 number, since 2×67721012775² (a number of 22 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a self number, because there is not a number n which added to its sum of digits gives 67721012775.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (67721012771) by changing a digit.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 1059990 + ... + 1122060.

Almost surely, 2^67721012775 is an apocalyptic number.

67721012775 is a gapful number since it is divisible by the number (65) formed by its first and last digit.

67721012775 is a deficient number, since it is larger than the sum of its proper divisors (63257611001).

67721012775 is a wasteful number, since it uses less digits than its factorization.

67721012775 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 62473 (or 62465 counting only the distinct ones).

The product of its (nonzero) digits is 288120, while the sum is 45.

Subtracting from 67721012775 its reverse (57721012776), we obtain a palindrome (9999999999).

The spelling of 67721012775 in words is "sixty-seven billion, seven hundred twenty-one million, twelve thousand, seven hundred seventy-five".