1640753484561 has 9 divisors (see below), whose sum is σ = 2369982806139. Its totient is φ = 1093833094536.

The previous prime is 1640753484553. The next prime is 1640753484619. The reversal of 1640753484561 is 1654843570461.

The square root of 1640753484561 is 1280919.

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

1640753484561 is a `hidden beast` number, since 1 + 6 + 4 + 0 + 7 + 534 + 8 + 45 + 61 = 666.

It can be written as a sum of positive squares in only one way, i.e., 179449668225 + 1461303816336 = 423615^2 + 1208844^2 .

It is a tau number, because it is divible by the number of its divisors (9).

It is not a de Polignac number, because 1640753484561 - 2³ = 1640753484553 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 1640753484498 and 1640753484507.

It is not an unprimeable number, because it can be changed into a prime (1640753484521) 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, 3629271 + ... + 4056243.

Almost surely, 2^{1640753484561} is an apocalyptic number.

1640753484561 is the 1280919-th square number.

1640753484561 is the 640460-th centered octagonal number.

It is an amenable number.

1640753484561 is a deficient number, since it is larger than the sum of its proper divisors (729229321578).

1640753484561 is an frugal number, since it uses more digits than its factorization.

1640753484561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 853952 (or 426976 counting only the distinct ones).

The product of its (nonzero) digits is 9676800, while the sum is 54.

The spelling of 1640753484561 in words is "one trillion, six hundred forty billion, seven hundred fifty-three million, four hundred eighty-four thousand, five hundred sixty-one".