1247771879 has 2 divisors, whose sum is σ = 1247771880. Its totient is φ = 1247771878.

The previous prime is 1247771869. The next prime is 1247771891. The reversal of 1247771879 is 9781777421.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 1247771879 - 2¹² = 1247767783 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1247771879.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1247771809) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 623885939 + 623885940.

It is an arithmetic number, because the mean of its divisors is an integer number (623885940).

Almost surely, 2^1247771879 is an apocalyptic number.

1247771879 is a deficient number, since it is larger than the sum of its proper divisors (1).

1247771879 is an equidigital number, since it uses as much as digits as its factorization.

1247771879 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1382976, while the sum is 53.

The square root of 1247771879 is about 35323.8146156386. The cubic root of 1247771879 is about 1076.5769188558.

The spelling of 1247771879 in words is "one billion, two hundred forty-seven million, seven hundred seventy-one thousand, eight hundred seventy-nine".