691721113 has 4 divisors (see below), whose sum is σ = 721795968. Its totient is φ = 661646260.

The previous prime is 691721099. The next prime is 691721131. The reversal of 691721113 is 311127196.

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 a de Polignac number, because none of the positive numbers 2^k-691721113 is a prime.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (691721153) 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, 15037393 + ... + 15037438.

It is an arithmetic number, because the mean of its divisors is an integer number (180448992).

Almost surely, 2^691721113 is an apocalyptic number.

It is an amenable number.

691721113 is a deficient number, since it is larger than the sum of its proper divisors (30074855).

691721113 is a wasteful number, since it uses less digits than its factorization.

691721113 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 30074854.

The product of its digits is 2268, while the sum is 31.

The square root of 691721113 is about 26300.5914952497. The cubic root of 691721113 is about 884.3897025495.

The spelling of 691721113 in words is "six hundred ninety-one million, seven hundred twenty-one thousand, one hundred thirteen".