691242097 has 16 divisors (see below), whose sum is σ = 895538560. Its totient is φ = 518130432.

The previous prime is 691242091. The next prime is 691242107. The reversal of 691242097 is 790242196.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-691242097 is a prime.

It is not an unprimeable number, because it can be changed into a prime (691242091) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 198168 + ... + 201625.

It is an arithmetic number, because the mean of its divisors is an integer number (55971160).

Almost surely, 2^691242097 is an apocalyptic number.

It is an amenable number.

691242097 is a deficient number, since it is larger than the sum of its proper divisors (204296463).

691242097 is a wasteful number, since it uses less digits than its factorization.

691242097 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 399832.

The product of its (nonzero) digits is 54432, while the sum is 40.

The square root of 691242097 is about 26291.4833548813. The cubic root of 691242097 is about 884.1855091558.

Subtracting 691242097 from its reverse (790242196), we obtain a palindrome (99000099).

The spelling of 691242097 in words is "six hundred ninety-one million, two hundred forty-two thousand, ninety-seven".