1285023661 has 4 divisors (see below), whose sum is σ = 1286112924. Its totient is φ = 1283934400.

The previous prime is 1285023643. The next prime is 1285023667. The reversal of 1285023661 is 1663205821.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 551968036 + 733055625 = 23494^2 + 27075^2 .

It is a cyclic number.

It is not a de Polignac number, because 1285023661 - 2⁵ = 1285023629 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 (1285023667) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 542860 + ... + 545221.

It is an arithmetic number, because the mean of its divisors is an integer number (321528231).

Almost surely, 2^1285023661 is an apocalyptic number.

It is an amenable number.

1285023661 is a deficient number, since it is larger than the sum of its proper divisors (1089263).

1285023661 is a wasteful number, since it uses less digits than its factorization.

1285023661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1089262.

The product of its (nonzero) digits is 17280, while the sum is 34.

The square root of 1285023661 is about 35847.2266849194. The cubic root of 1285023661 is about 1087.1856417499.

The spelling of 1285023661 in words is "one billion, two hundred eighty-five million, twenty-three thousand, six hundred sixty-one".