691654637 has 4 divisors (see below), whose sum is σ = 691773756. Its totient is φ = 691535520.

The previous prime is 691654619. The next prime is 691654657. The reversal of 691654637 is 736456196.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 244797316 + 446857321 = 15646^2 + 21139^2 .

It is a cyclic number.

It is not a de Polignac number, because 691654637 - 2²⁴ = 674877421 is a prime.

It is a super-2 number, since 2×691654637² = 956772273767203538, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 691654591 and 691654600.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (691654657) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 50378 + ... + 62619.

It is an arithmetic number, because the mean of its divisors is an integer number (172943439).

Almost surely, 2^691654637 is an apocalyptic number.

It is an amenable number.

691654637 is a deficient number, since it is larger than the sum of its proper divisors (119119).

691654637 is a wasteful number, since it uses less digits than its factorization.

691654637 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 119118.

The product of its digits is 816480, while the sum is 47.

The square root of 691654637 is about 26299.3276910266. The cubic root of 691654637 is about 884.3613710095.

The spelling of 691654637 in words is "six hundred ninety-one million, six hundred fifty-four thousand, six hundred thirty-seven".