1281681361 has 16 divisors (see below), whose sum is σ = 1361480400. Its totient is φ = 1204403200.

The previous prime is 1281681343. The next prime is 1281681377. The reversal of 1281681361 is 1631861821.

It can be written as a sum of positive squares in 8 ways, for example, as 372297025 + 909384336 = 19295^2 + 30156^2 .

It is a cyclic number.

It is not a de Polignac number, because 1281681361 - 2⁹ = 1281680849 is a prime.

It is a super-2 number, since 2×1281681361² = 3285414222269624642, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 1281681361.

It is not an unprimeable number, because it can be changed into a prime (1281681301) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 618435 + ... + 620503.

It is an arithmetic number, because the mean of its divisors is an integer number (85092525).

Almost surely, 2^1281681361 is an apocalyptic number.

It is an amenable number.

1281681361 is a deficient number, since it is larger than the sum of its proper divisors (79799039).

1281681361 is a wasteful number, since it uses less digits than its factorization.

1281681361 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2660.

The product of its digits is 13824, while the sum is 37.

The square root of 1281681361 is about 35800.5776629372. The cubic root of 1281681361 is about 1086.2422465384.

The spelling of 1281681361 in words is "one billion, two hundred eighty-one million, six hundred eighty-one thousand, three hundred sixty-one".