631121389 has 2 divisors, whose sum is σ = 631121390. Its totient is φ = 631121388.

The previous prime is 631121383. The next prime is 631121411. The reversal of 631121389 is 983121136.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 337273225 + 293848164 = 18365^2 + 17142^2 .

It is a cyclic number.

It is not a de Polignac number, because 631121389 - 2¹⁵ = 631088621 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (631121383) 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, 315560694 + 315560695.

It is an arithmetic number, because the mean of its divisors is an integer number (315560695).

Almost surely, 2^631121389 is an apocalyptic number.

It is an amenable number.

631121389 is a deficient number, since it is larger than the sum of its proper divisors (1).

631121389 is an equidigital number, since it uses as much as digits as its factorization.

631121389 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 7776, while the sum is 34.

The square root of 631121389 is about 25122.1294678616. The cubic root of 631121389 is about 857.7702238054.

The spelling of 631121389 in words is "six hundred thirty-one million, one hundred twenty-one thousand, three hundred eighty-nine".