691027087 has 2 divisors, whose sum is σ = 691027088. Its totient is φ = 691027086.

The previous prime is 691027081. The next prime is 691027121. The reversal of 691027087 is 780720196.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-691027087 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (691027081) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 345513543 + 345513544.

It is an arithmetic number, because the mean of its divisors is an integer number (345513544).

Almost surely, 2^691027087 is an apocalyptic number.

691027087 is a deficient number, since it is larger than the sum of its proper divisors (1).

691027087 is an equidigital number, since it uses as much as digits as its factorization.

691027087 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 42336, while the sum is 40.

The square root of 691027087 is about 26287.3940701622. The cubic root of 691027087 is about 884.0938247124.

The spelling of 691027087 in words is "six hundred ninety-one million, twenty-seven thousand, eighty-seven".