691255663 has 16 divisors (see below), whose sum is σ = 832320000. Its totient is φ = 560824992.

The previous prime is 691255651. The next prime is 691255673. The reversal of 691255663 is 366552196.

It is a de Polignac number, because none of the positive numbers 2^k-691255663 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (691255603) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 269913 + ... + 272461.

It is an arithmetic number, because the mean of its divisors is an integer number (52020000).

Almost surely, 2^691255663 is an apocalyptic number.

691255663 is a deficient number, since it is larger than the sum of its proper divisors (141064337).

691255663 is a wasteful number, since it uses less digits than its factorization.

691255663 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4614.

The product of its digits is 291600, while the sum is 43.

The square root of 691255663 is about 26291.7413459056. The cubic root of 691255663 is about 884.1912933243.

The spelling of 691255663 in words is "six hundred ninety-one million, two hundred fifty-five thousand, six hundred sixty-three".