689095591021 has 2 divisors, whose sum is σ = 689095591022. Its totient is φ = 689095591020.

The previous prime is 689095590979. The next prime is 689095591069. The reversal of 689095591021 is 120195590986.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 507248781796 + 181846809225 = 712214^2 + 426435^2 .

It is a cyclic number.

It is not a de Polignac number, because 689095591021 - 2⁷ = 689095590893 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (689095591091) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 344547795510 + 344547795511.

It is an arithmetic number, because the mean of its divisors is an integer number (344547795511).

Almost surely, 2^689095591021 is an apocalyptic number.

It is an amenable number.

689095591021 is a deficient number, since it is larger than the sum of its proper divisors (1).

689095591021 is an equidigital number, since it uses as much as digits as its factorization.

689095591021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1749600, while the sum is 55.

It can be divided in two parts, 68909 and 5591021, that added together give a triangular number (5659930 = T₃₃₆₄).

The spelling of 689095591021 in words is "six hundred eighty-nine billion, ninety-five million, five hundred ninety-one thousand, twenty-one".