1240420789 has 2 divisors, whose sum is σ = 1240420790. Its totient is φ = 1240420788.

The previous prime is 1240420721. The next prime is 1240420813. The reversal of 1240420789 is 9870240421.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 628254225 + 612166564 = 25065^2 + 24742^2 .

It is an emirp because it is prime and its reverse (9870240421) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1240420789 - 2¹³ = 1240412597 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (5240420789) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 620210394 + 620210395.

It is an arithmetic number, because the mean of its divisors is an integer number (620210395).

Almost surely, 2^1240420789 is an apocalyptic number.

It is an amenable number.

1240420789 is a deficient number, since it is larger than the sum of its proper divisors (1).

1240420789 is an equidigital number, since it uses as much as digits as its factorization.

1240420789 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 32256, while the sum is 37.

The square root of 1240420789 is about 35219.6080188295. The cubic root of 1240420789 is about 1074.4585812297.

The spelling of 1240420789 in words is "one billion, two hundred forty million, four hundred twenty thousand, seven hundred eighty-nine".