1661402913861 has 8 divisors (see below), whose sum is σ = 2215233535680. Its totient is φ = 1107587117312.

The previous prime is 1661402913719. The next prime is 1661402913869. The reversal of 1661402913861 is 1683192041661.

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 1661402913861 - 2¹¹ = 1661402911813 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1661402913861.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1661402913869) 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, 3442140 + ... + 3895013.

It is an arithmetic number, because the mean of its divisors is an integer number (276904191960).

Almost surely, 2^{1661402913861} is an apocalyptic number.

It is an amenable number.

1661402913861 is a deficient number, since it is larger than the sum of its proper divisors (553830621819).

1661402913861 is an equidigital number, since it uses as much as digits as its factorization.

1661402913861 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7412635.

The product of its (nonzero) digits is 373248, while the sum is 48.

The spelling of 1661402913861 in words is "one trillion, six hundred sixty-one billion, four hundred two million, nine hundred thirteen thousand, eight hundred sixty-one".