689812621 has 4 divisors (see below), whose sum is σ = 730389852. Its totient is φ = 649235392.

The previous prime is 689812603. The next prime is 689812633. The reversal of 689812621 is 126218986.

It is a happy number.

689812621 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.

It can be written as a sum of positive squares in 2 ways, for example, as 264875625 + 424936996 = 16275^2 + 20614^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-689812621 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (689812421) 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, 20288590 + ... + 20288623.

It is an arithmetic number, because the mean of its divisors is an integer number (182597463).

Almost surely, 2^689812621 is an apocalyptic number.

It is an amenable number.

689812621 is a deficient number, since it is larger than the sum of its proper divisors (40577231).

689812621 is a wasteful number, since it uses less digits than its factorization.

689812621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 40577230.

The product of its digits is 82944, while the sum is 43.

The square root of 689812621 is about 26264.2841326391. The cubic root of 689812621 is about 883.5755953844.

The spelling of 689812621 in words is "six hundred eighty-nine million, eight hundred twelve thousand, six hundred twenty-one".