691247093 has 2 divisors, whose sum is σ = 691247094. Its totient is φ = 691247092.

The previous prime is 691246981. The next prime is 691247143. The reversal of 691247093 is 390742196.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 381733444 + 309513649 = 19538^2 + 17593^2 .

It is a cyclic number.

It is not a de Polignac number, because 691247093 - 2¹⁰ = 691246069 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 691247093.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (691247993) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 345623546 + 345623547.

It is an arithmetic number, because the mean of its divisors is an integer number (345623547).

Almost surely, 2^691247093 is an apocalyptic number.

It is an amenable number.

691247093 is a deficient number, since it is larger than the sum of its proper divisors (1).

691247093 is an equidigital number, since it uses as much as digits as its factorization.

691247093 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 81648, while the sum is 41.

The square root of 691247093 is about 26291.5783664656. The cubic root of 691247093 is about 884.1876393213.

The spelling of 691247093 in words is "six hundred ninety-one million, two hundred forty-seven thousand, ninety-three".