1781421061 has 4 divisors (see below), whose sum is σ = 2035909792. Its totient is φ = 1526932332.

The previous prime is 1781421049. The next prime is 1781421091. The reversal of 1781421061 is 1601241871.

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, and also an emirpimes, since its reverse is a distinct semiprime: 1601241871 = 11423 ⋅140177.

It is a cyclic number.

It is not a de Polignac number, because 1781421061 - 2⁵ = 1781421029 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1781421011) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 127244355 + ... + 127244368.

It is an arithmetic number, because the mean of its divisors is an integer number (508977448).

Almost surely, 2^1781421061 is an apocalyptic number.

It is an amenable number.

1781421061 is a deficient number, since it is larger than the sum of its proper divisors (254488731).

1781421061 is an equidigital number, since it uses as much as digits as its factorization.

1781421061 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 254488730.

The product of its (nonzero) digits is 2688, while the sum is 31.

The square root of 1781421061 is about 42206.8840475105. The cubic root of 1781421061 is about 1212.2406995161.

The spelling of 1781421061 in words is "one billion, seven hundred eighty-one million, four hundred twenty-one thousand, sixty-one".