691827878780 has 24 divisors (see below), whose sum is σ = 1529303732880. Its totient is φ = 262166353920.

The previous prime is 691827878719. The next prime is 691827878831. The reversal of 691827878780 is 87878728196.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 910299461 + ... + 910300220.

It is an arithmetic number, because the mean of its divisors is an integer number (63720988870).

Almost surely, 2^691827878780 is an apocalyptic number.

It is an amenable number.

691827878780 is an abundant number, since it is smaller than the sum of its proper divisors (837475854100).

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

691827878780 is a wasteful number, since it uses less digits than its factorization.

691827878780 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1820599709 (or 1820599707 counting only the distinct ones).

The product of its (nonzero) digits is 151732224, while the sum is 71.

The spelling of 691827878780 in words is "six hundred ninety-one billion, eight hundred twenty-seven million, eight hundred seventy-eight thousand, seven hundred eighty".