1278229397 has 4 divisors (see below), whose sum is σ = 1279833996. Its totient is φ = 1276624800.

The previous prime is 1278229391. The next prime is 1278229399. The reversal of 1278229397 is 7939228721.

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 798006001 + 480223396 = 28249^2 + 21914^2 .

It is a cyclic number.

It is not a de Polignac number, because 1278229397 - 2⁶ = 1278229333 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 (1278229391) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 801104 + ... + 802697.

It is an arithmetic number, because the mean of its divisors is an integer number (319958499).

Almost surely, 2^1278229397 is an apocalyptic number.

It is an amenable number.

1278229397 is a deficient number, since it is larger than the sum of its proper divisors (1604599).

1278229397 is an equidigital number, since it uses as much as digits as its factorization.

1278229397 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1604598.

The product of its digits is 762048, while the sum is 50.

The square root of 1278229397 is about 35752.3341475770. The cubic root of 1278229397 is about 1085.2661743700.

The spelling of 1278229397 in words is "one billion, two hundred seventy-eight million, two hundred twenty-nine thousand, three hundred ninety-seven".