684721495441 has 9 divisors (see below), whose sum is σ = 686978811963. Its totient is φ = 682471580040.

The previous prime is 684721495397. The next prime is 684721495519. The reversal of 684721495441 is 144594127486.

The square root of 684721495441 is 827479.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 502580327041 + 182141168400 = 708929^2 + 426780^2 .

It is not a de Polignac number, because 684721495441 - 2⁷ = 684721495313 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (684721495541) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 288788986 + ... + 288791356.

It is an arithmetic number, because the mean of its divisors is an integer number (76330979107).

Almost surely, 2^684721495441 is an apocalyptic number.

684721495441 is the 827479-th square number.

684721495441 is the 413740-th centered octagonal number.

It is an amenable number.

684721495441 is a deficient number, since it is larger than the sum of its proper divisors (2257316522).

684721495441 is an frugal number, since it uses more digits than its factorization.

684721495441 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5440 (or 2720 counting only the distinct ones).

The product of its digits is 7741440, while the sum is 55.

The spelling of 684721495441 in words is "six hundred eighty-four billion, seven hundred twenty-one million, four hundred ninety-five thousand, four hundred forty-one".