690824786521 has 2 divisors, whose sum is σ = 690824786522. Its totient is φ = 690824786520.

The previous prime is 690824786513. The next prime is 690824786569. The reversal of 690824786521 is 125687428096.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 688881740121 + 1943046400 = 829989^2 + 44080^2 .

It is a cyclic number.

It is not a de Polignac number, because 690824786521 - 2³ = 690824786513 is a prime.

It is not a weakly prime, because it can be changed into another prime (690824786221) 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 as a sum of consecutive naturals, namely, 345412393260 + 345412393261.

It is an arithmetic number, because the mean of its divisors is an integer number (345412393261).

Almost surely, 2^690824786521 is an apocalyptic number.

It is an amenable number.

690824786521 is a deficient number, since it is larger than the sum of its proper divisors (1).

690824786521 is an equidigital number, since it uses as much as digits as its factorization.

690824786521 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 11612160, while the sum is 58.

The spelling of 690824786521 in words is "six hundred ninety billion, eight hundred twenty-four million, seven hundred eighty-six thousand, five hundred twenty-one".