1261938789 has 12 divisors (see below), whose sum is σ = 1918737600. Its totient is φ = 797013864.

The previous prime is 1261938763. The next prime is 1261938817. The reversal of 1261938789 is 9878391621.

1261938789 is a `hidden beast` number, since 12 + 619 + 3 + 8 + 7 + 8 + 9 = 666.

It is not a de Polignac number, because 1261938789 - 2⁷ = 1261938661 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1261938709) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 3689709 + ... + 3690050.

It is an arithmetic number, because the mean of its divisors is an integer number (159894800).

Almost surely, 2^1261938789 is an apocalyptic number.

1261938789 is a gapful number since it is divisible by the number (19) formed by its first and last digit.

It is an amenable number.

1261938789 is a deficient number, since it is larger than the sum of its proper divisors (656798811).

1261938789 is a wasteful number, since it uses less digits than its factorization.

1261938789 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7379784 (or 7379781 counting only the distinct ones).

The product of its digits is 1306368, while the sum is 54.

The square root of 1261938789 is about 35523.7777974134. Note that the first 4 decimals coincide. The cubic root of 1261938789 is about 1080.6359962823.

The spelling of 1261938789 in words is "one billion, two hundred sixty-one million, nine hundred thirty-eight thousand, seven hundred eighty-nine".