1242778681 has 16 divisors (see below), whose sum is σ = 1304281600. Its totient is φ = 1182962880.

The previous prime is 1242778643. The next prime is 1242778697. The reversal of 1242778681 is 1868772421.

It is a cyclic number.

It is not a de Polignac number, because 1242778681 - 2⁷ = 1242778553 is a prime.

It is a super-2 number, since 2×1242778681² = 3088997699896199522, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1242778601) 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 15 ways as a sum of consecutive naturals, for example, 447760 + ... + 450526.

It is an arithmetic number, because the mean of its divisors is an integer number (81517600).

Almost surely, 2^1242778681 is an apocalyptic number.

It is an amenable number.

1242778681 is a deficient number, since it is larger than the sum of its proper divisors (61502919).

1242778681 is a wasteful number, since it uses less digits than its factorization.

1242778681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3064.

The product of its digits is 301056, while the sum is 46.

The square root of 1242778681 is about 35253.0662638018. The cubic root of 1242778681 is about 1075.1389561857.

The spelling of 1242778681 in words is "one billion, two hundred forty-two million, seven hundred seventy-eight thousand, six hundred eighty-one".