1356781121 has 2 divisors, whose sum is σ = 1356781122. Its totient is φ = 1356781120.

The previous prime is 1356781099. The next prime is 1356781141. The reversal of 1356781121 is 1211876531.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1227731521 + 129049600 = 35039^2 + 11360^2 .

It is an emirp because it is prime and its reverse (1211876531) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1356781121 - 2⁶ = 1356781057 is a prime.

It is not a weakly prime, because it can be changed into another prime (1356781141) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 678390560 + 678390561.

It is an arithmetic number, because the mean of its divisors is an integer number (678390561).

Almost surely, 2^1356781121 is an apocalyptic number.

It is an amenable number.

1356781121 is a deficient number, since it is larger than the sum of its proper divisors (1).

1356781121 is an equidigital number, since it uses as much as digits as its factorization.

1356781121 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 10080, while the sum is 35.

The square root of 1356781121 is about 36834.5099193677. The cubic root of 1356781121 is about 1107.0568682063.

The spelling of 1356781121 in words is "one billion, three hundred fifty-six million, seven hundred eighty-one thousand, one hundred twenty-one".