691988948841 has 4 divisors (see below), whose sum is σ = 922651931792. Its totient is φ = 461325965892.

The previous prime is 691988948741. The next prime is 691988948843. The reversal of 691988948841 is 148849889196.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 691988948841 - 2¹⁷ = 691988817769 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (691988948843) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 115331491471 + ... + 115331491476.

It is an arithmetic number, because the mean of its divisors is an integer number (230662982948).

Almost surely, 2^691988948841 is an apocalyptic number.

It is an amenable number.

691988948841 is a deficient number, since it is larger than the sum of its proper divisors (230662982951).

691988948841 is a wasteful number, since it uses less digits than its factorization.

691988948841 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 230662982950.

The product of its digits is 286654464, while the sum is 75.

The spelling of 691988948841 in words is "six hundred ninety-one billion, nine hundred eighty-eight million, nine hundred forty-eight thousand, eight hundred forty-one".