691506149 has 2 divisors, whose sum is σ = 691506150. Its totient is φ = 691506148.

The previous prime is 691506103. The next prime is 691506191. The reversal of 691506149 is 941605196.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 656281924 + 35224225 = 25618^2 + 5935^2 .

It is a cyclic number.

It is not a de Polignac number, because 691506149 - 2¹⁶ = 691440613 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (691506199) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 345753074 + 345753075.

It is an arithmetic number, because the mean of its divisors is an integer number (345753075).

Almost surely, 2^691506149 is an apocalyptic number.

It is an amenable number.

691506149 is a deficient number, since it is larger than the sum of its proper divisors (1).

691506149 is an equidigital number, since it uses as much as digits as its factorization.

691506149 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 58320, while the sum is 41.

The square root of 691506149 is about 26296.5045015493. The cubic root of 691506149 is about 884.2980800535.

The spelling of 691506149 in words is "six hundred ninety-one million, five hundred six thousand, one hundred forty-nine".