690908557309 has 2 divisors, whose sum is σ = 690908557310. Its totient is φ = 690908557308.

The previous prime is 690908557271. The next prime is 690908557343. The reversal of 690908557309 is 903755809096.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 510648872409 + 180259684900 = 714597^2 + 424570^2 .

It is a cyclic number.

It is not a de Polignac number, because 690908557309 - 2¹³ = 690908549117 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (690908557349) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 345454278654 + 345454278655.

It is an arithmetic number, because the mean of its divisors is an integer number (345454278655).

Almost surely, 2^690908557309 is an apocalyptic number.

It is an amenable number.

690908557309 is a deficient number, since it is larger than the sum of its proper divisors (1).

690908557309 is an equidigital number, since it uses as much as digits as its factorization.

690908557309 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 18370800, while the sum is 61.

The spelling of 690908557309 in words is "six hundred ninety billion, nine hundred eight million, five hundred fifty-seven thousand, three hundred nine".