1646780507561 has 8 divisors (see below), whose sum is σ = 1882049215680. Its totient is φ = 1411515386928.

The previous prime is 1646780507527. The next prime is 1646780507563. The reversal of 1646780507561 is 1657050876461.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 1646780507561 - 2²² = 1646776313257 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1646780507497 and 1646780507506.

It is not an unprimeable number, because it can be changed into a prime (1646780507563) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 171650 + ... + 1822916.

It is an arithmetic number, because the mean of its divisors is an integer number (235256151960).

Almost surely, 2^{1646780507561} is an apocalyptic number.

It is an amenable number.

1646780507561 is a deficient number, since it is larger than the sum of its proper divisors (235268708119).

1646780507561 is a wasteful number, since it uses less digits than its factorization.

1646780507561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1793743.

The product of its (nonzero) digits is 8467200, while the sum is 56.

The spelling of 1646780507561 in words is "one trillion, six hundred forty-six billion, seven hundred eighty million, five hundred seven thousand, five hundred sixty-one".