1278974621 has 2 divisors, whose sum is σ = 1278974622. Its totient is φ = 1278974620.

The previous prime is 1278974573. The next prime is 1278974647. The reversal of 1278974621 is 1264798721.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 754106521 + 524868100 = 27461^2 + 22910^2 .

It is a cyclic number.

It is not a de Polignac number, because 1278974621 - 2¹⁴ = 1278958237 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1278974321) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 639487310 + 639487311.

It is an arithmetic number, because the mean of its divisors is an integer number (639487311).

Almost surely, 2^1278974621 is an apocalyptic number.

It is an amenable number.

1278974621 is a deficient number, since it is larger than the sum of its proper divisors (1).

1278974621 is an equidigital number, since it uses as much as digits as its factorization.

1278974621 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 338688, while the sum is 47.

The square root of 1278974621 is about 35762.7546617986. The cubic root of 1278974621 is about 1085.4770413914.

The spelling of 1278974621 in words is "one billion, two hundred seventy-eight million, nine hundred seventy-four thousand, six hundred twenty-one".