690688881698 has 4 divisors (see below), whose sum is σ = 1036033322550. Its totient is φ = 345344440848.

The previous prime is 690688881677. The next prime is 690688881703. The reversal of 690688881698 is 896188886096.

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., 403818308089 + 286870573609 = 635467^2 + 535603^2 .

It is a super-2 number, since 2×690688881698² (a number of 24 digits) contains 22 as substring.

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 172672220423 + ... + 172672220426.

Almost surely, 2^690688881698 is an apocalyptic number.

690688881698 is a deficient number, since it is larger than the sum of its proper divisors (345344440852).

690688881698 is a wasteful number, since it uses less digits than its factorization.

690688881698 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 345344440851.

The product of its (nonzero) digits is 573308928, while the sum is 77.

The spelling of 690688881698 in words is "six hundred ninety billion, six hundred eighty-eight million, eight hundred eighty-one thousand, six hundred ninety-eight".