1661564132293 has 4 divisors (see below), whose sum is σ = 1789376757868. Its totient is φ = 1533751506720.

The previous prime is 1661564132279. The next prime is 1661564132297. The reversal of 1661564132293 is 3922314651661.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 978233749249 + 683330383044 = 989057^2 + 826638^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1661564132293 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1661564132297) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 63906312768 + ... + 63906312793.

It is an arithmetic number, because the mean of its divisors is an integer number (447344189467).

Almost surely, 2^{1661564132293} is an apocalyptic number.

1661564132293 is a gapful number since it is divisible by the number (13) formed by its first and last digit.

It is an amenable number.

1661564132293 is a deficient number, since it is larger than the sum of its proper divisors (127812625575).

1661564132293 is a wasteful number, since it uses less digits than its factorization.

1661564132293 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 127812625574.

The product of its digits is 1399680, while the sum is 49.

The spelling of 1661564132293 in words is "one trillion, six hundred sixty-one billion, five hundred sixty-four million, one hundred thirty-two thousand, two hundred ninety-three".