691216437 has 8 divisors (see below), whose sum is σ = 936730720. Its totient is φ = 453256560.

The previous prime is 691216403. The next prime is 691216439. The reversal of 691216437 is 734612196.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 691216437 - 2⁶ = 691216373 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 691216395 and 691216404.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (691216439) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1888387 + ... + 1888752.

It is an arithmetic number, because the mean of its divisors is an integer number (117091340).

Almost surely, 2^691216437 is an apocalyptic number.

It is an amenable number.

691216437 is a deficient number, since it is larger than the sum of its proper divisors (245514283).

691216437 is a wasteful number, since it uses less digits than its factorization.

691216437 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3777203.

The product of its digits is 54432, while the sum is 39.

The square root of 691216437 is about 26290.9953596284. The cubic root of 691216437 is about 884.1745682322.

The spelling of 691216437 in words is "six hundred ninety-one million, two hundred sixteen thousand, four hundred thirty-seven".