691281641 has 4 divisors (see below), whose sum is σ = 691353300. Its totient is φ = 691209984.

The previous prime is 691281599. The next prime is 691281653. The reversal of 691281641 is 146182196.

691281641 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 478734400 + 212547241 = 21880^2 + 14579^2 .

It is a cyclic number.

It is not a de Polignac number, because 691281641 - 2²² = 687087337 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 691281595 and 691281604.

It is not an unprimeable number, because it can be changed into a prime (691281691) 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, 18596 + ... + 41573.

It is an arithmetic number, because the mean of its divisors is an integer number (172838325).

Almost surely, 2^691281641 is an apocalyptic number.

It is an amenable number.

691281641 is a deficient number, since it is larger than the sum of its proper divisors (71659).

691281641 is a wasteful number, since it uses less digits than its factorization.

691281641 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 71658.

The product of its digits is 20736, while the sum is 38.

The square root of 691281641 is about 26292.2353747261. The cubic root of 691281641 is about 884.2023694161.

The spelling of 691281641 in words is "six hundred ninety-one million, two hundred eighty-one thousand, six hundred forty-one".