691047150218 has 4 divisors (see below), whose sum is σ = 1036570725330. Its totient is φ = 345523575108.

The previous prime is 691047150107. The next prime is 691047150223. The reversal of 691047150218 is 812051740196.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 527696186329 + 163350963889 = 726427^2 + 404167^2 .

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 as a sum of consecutive naturals, namely, 172761787553 + ... + 172761787556.

Almost surely, 2^691047150218 is an apocalyptic number.

691047150218 is a deficient number, since it is larger than the sum of its proper divisors (345523575112).

691047150218 is a wasteful number, since it uses less digits than its factorization.

691047150218 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 345523575111.

The product of its (nonzero) digits is 120960, while the sum is 44.

The spelling of 691047150218 in words is "six hundred ninety-one billion, forty-seven million, one hundred fifty thousand, two hundred eighteen".