1278448721 has 16 divisors (see below), whose sum is σ = 1463771520. Its totient is φ = 1105230720.

The previous prime is 1278448709. The next prime is 1278448727.

1278448721 is nontrivially palindromic in base 10.

It is not a de Polignac number, because 1278448721 - 2⁶ = 1278448657 is a prime.

It is a super-2 number, since 2×1278448721² = 3268862264453071682, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (1278448727) 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, 29165 + ... + 58373.

It is an arithmetic number, because the mean of its divisors is an integer number (91485720).

Almost surely, 2^1278448721 is an apocalyptic number.

1278448721 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1278448721 is a deficient number, since it is larger than the sum of its proper divisors (185322799).

1278448721 is a wasteful number, since it uses less digits than its factorization.

1278448721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 29416.

The product of its digits is 200704, while the sum is 44.

The square root of 1278448721 is about 35755.4012842815. The cubic root of 1278448721 is about 1085.3282423386.

The spelling of 1278448721 in words is "one billion, two hundred seventy-eight million, four hundred forty-eight thousand, seven hundred twenty-one".