699561521 has 2 divisors, whose sum is σ = 699561522. Its totient is φ = 699561520.

The previous prime is 699561493. The next prime is 699561559. The reversal of 699561521 is 125165996.

699561521 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 609102400 + 90459121 = 24680^2 + 9511^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-699561521 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (699561571) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 349780760 + 349780761.

It is an arithmetic number, because the mean of its divisors is an integer number (349780761).

Almost surely, 2^699561521 is an apocalyptic number.

It is an amenable number.

699561521 is a deficient number, since it is larger than the sum of its proper divisors (1).

699561521 is an equidigital number, since it uses as much as digits as its factorization.

699561521 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 145800, while the sum is 44.

The square root of 699561521 is about 26449.2253383724. The cubic root of 699561521 is about 887.7185690862.

The spelling of 699561521 in words is "six hundred ninety-nine million, five hundred sixty-one thousand, five hundred twenty-one".