691831221506 has 8 divisors (see below), whose sum is σ = 1037986012560. Its totient is φ = 345835883988.

The previous prime is 691831221463. The next prime is 691831221517. The reversal of 691831221506 is 605122138196.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 39852536 + ... + 39869891.

It is an arithmetic number, because the mean of its divisors is an integer number (129748251570).

Almost surely, 2^691831221506 is an apocalyptic number.

691831221506 is a deficient number, since it is larger than the sum of its proper divisors (346154791054).

691831221506 is a wasteful number, since it uses less digits than its factorization.

691831221506 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 79726768.

The product of its (nonzero) digits is 155520, while the sum is 44.

The spelling of 691831221506 in words is "six hundred ninety-one billion, eight hundred thirty-one million, two hundred twenty-one thousand, five hundred six".