691921607 has 16 divisors (see below), whose sum is σ = 792993600. Its totient is φ = 598067712.

The previous prime is 691921603. The next prime is 691921621. The reversal of 691921607 is 706129196.

It is a cyclic number.

It is not a de Polignac number, because 691921607 - 2² = 691921603 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 (691921603) 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 in 15 ways as a sum of consecutive naturals, for example, 36113 + ... + 51845.

It is an arithmetic number, because the mean of its divisors is an integer number (49562100).

Almost surely, 2^691921607 is an apocalyptic number.

691921607 is a deficient number, since it is larger than the sum of its proper divisors (101071993).

691921607 is a wasteful number, since it uses less digits than its factorization.

691921607 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15962.

The product of its (nonzero) digits is 40824, while the sum is 41.

The square root of 691921607 is about 26304.4028063744. The cubic root of 691921607 is about 884.4751404989.

The spelling of 691921607 in words is "six hundred ninety-one million, nine hundred twenty-one thousand, six hundred seven".