1201385781 has 12 divisors (see below), whose sum is σ = 1735881420. Its totient is φ = 800671680.

The previous prime is 1201385771. The next prime is 1201385831. The reversal of 1201385781 is 1875831021.

1201385781 is a `hidden beast` number, since 1 + 201 + 385 + 78 + 1 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 504900900 + 696484881 = 22470^2 + 26391^2 .

It is not a de Polignac number, because 1201385781 - 2¹⁷ = 1201254709 is a prime.

It is a super-2 number, since 2×1201385781² = 2886655589577959922, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1201385771) 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 11 ways as a sum of consecutive naturals, for example, 11865 + ... + 50433.

It is an arithmetic number, because the mean of its divisors is an integer number (144656785).

Almost surely, 2^1201385781 is an apocalyptic number.

It is an amenable number.

1201385781 is a deficient number, since it is larger than the sum of its proper divisors (534495639).

1201385781 is a wasteful number, since it uses less digits than its factorization.

1201385781 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 42036 (or 42033 counting only the distinct ones).

The product of its (nonzero) digits is 13440, while the sum is 36.

The square root of 1201385781 is about 34661.0124058718. The cubic root of 1201385781 is about 1063.0674707248.

The spelling of 1201385781 in words is "one billion, two hundred one million, three hundred eighty-five thousand, seven hundred eighty-one".