1287709381 has 12 divisors (see below), whose sum is σ = 1494535008. Its totient is φ = 1086620832.

The previous prime is 1287709343. The next prime is 1287709457. The reversal of 1287709381 is 1839077821.

It is not a de Polignac number, because 1287709381 - 2¹⁵ = 1287676613 is a prime.

It is a super-2 number, since 2×1287709381² = 3316390899830806322, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1287709981) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 776305 + ... + 777961.

It is an arithmetic number, because the mean of its divisors is an integer number (124544584).

Almost surely, 2^1287709381 is an apocalyptic number.

It is an amenable number.

1287709381 is a deficient number, since it is larger than the sum of its proper divisors (206825627).

1287709381 is an frugal number, since it uses more digits than its factorization.

1287709381 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3388 (or 1731 counting only the distinct ones).

The product of its (nonzero) digits is 169344, while the sum is 46.

The square root of 1287709381 is about 35884.6677705117. The cubic root of 1287709381 is about 1087.9425264862.

The spelling of 1287709381 in words is "one billion, two hundred eighty-seven million, seven hundred nine thousand, three hundred eighty-one".