691395749 has 4 divisors (see below), whose sum is σ = 754249920. Its totient is φ = 628541580.

The previous prime is 691395737. The next prime is 691395767. The reversal of 691395749 is 947593196.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 691395749 - 2²⁰ = 690347173 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 691395749.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (691391749) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 31427069 + ... + 31427090.

It is an arithmetic number, because the mean of its divisors is an integer number (188562480).

Almost surely, 2^691395749 is an apocalyptic number.

It is an amenable number.

691395749 is a deficient number, since it is larger than the sum of its proper divisors (62854171).

691395749 is a wasteful number, since it uses less digits than its factorization.

691395749 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 62854170.

The product of its digits is 1837080, while the sum is 53.

The square root of 691395749 is about 26294.4052794506. The cubic root of 691395749 is about 884.2510177080.

The spelling of 691395749 in words is "six hundred ninety-one million, three hundred ninety-five thousand, seven hundred forty-nine".