1781181461 has 4 divisors (see below), whose sum is σ = 1781433312. Its totient is φ = 1780929612.

The previous prime is 1781181403. The next prime is 1781181469. The reversal of 1781181461 is 1641811871.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 1781181461 - 2¹⁸ = 1780919317 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 (1781181469) 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, 115001 + ... + 129566.

It is an arithmetic number, because the mean of its divisors is an integer number (445358328).

Almost surely, 2^1781181461 is an apocalyptic number.

It is an amenable number.

1781181461 is a deficient number, since it is larger than the sum of its proper divisors (251851).

1781181461 is an equidigital number, since it uses as much as digits as its factorization.

1781181461 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 251850.

The product of its digits is 10752, while the sum is 38.

The square root of 1781181461 is about 42204.0455525297. The cubic root of 1781181461 is about 1212.1863485448.

The spelling of 1781181461 in words is "one billion, seven hundred eighty-one million, one hundred eighty-one thousand, four hundred sixty-one".