68391721528 has 32 divisors (see below), whose sum is σ = 138196976400. Its totient is φ = 31542939648.

The previous prime is 68391721523. The next prime is 68391721547. The reversal of 68391721528 is 82512719386.

It is a happy number.

It is a Smith number, since the sum of its digits (52) coincides with the sum of the digits of its prime factors.

It is a Harshad number since it is a multiple of its sum of digits (52).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (68391721523) 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, 86826 + ... + 379897.

Almost surely, 2^68391721528 is an apocalyptic number.

It is an amenable number.

68391721528 is an abundant number, since it is smaller than the sum of its proper divisors (69805254872).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

68391721528 is a wasteful number, since it uses less digits than its factorization.

68391721528 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 468151 (or 468147 counting only the distinct ones).

The product of its digits is 1451520, while the sum is 52.

The spelling of 68391721528 in words is "sixty-eight billion, three hundred ninety-one million, seven hundred twenty-one thousand, five hundred twenty-eight".