1661414781 has 8 divisors (see below), whose sum is σ = 2385621280. Its totient is φ = 1022409072.

The previous prime is 1661414771. The next prime is 1661414789. The reversal of 1661414781 is 1874141661.

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

It is not a de Polignac number, because 1661414781 - 2¹³ = 1661406589 is a prime.

It is a super-2 number, since 2×1661414781² = 5520598149050555922, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (39), and also a Moran number because the ratio is a prime number: 42600379 = 1661414781 / (1 + 6 + 6 + 1 + 4 + 1 + 4 + 7 + 8 + 1).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1661414789) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 21300151 + ... + 21300228.

It is an arithmetic number, because the mean of its divisors is an integer number (298202660).

Almost surely, 2^1661414781 is an apocalyptic number.

It is an amenable number.

1661414781 is a deficient number, since it is larger than the sum of its proper divisors (724206499).

1661414781 is a wasteful number, since it uses less digits than its factorization.

1661414781 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 42600395.

The product of its digits is 32256, while the sum is 39.

The square root of 1661414781 is about 40760.4560941116. The cubic root of 1661414781 is about 1184.3844313068.

The spelling of 1661414781 in words is "one billion, six hundred sixty-one million, four hundred fourteen thousand, seven hundred eighty-one".