1287639126500 has 24 divisors (see below), whose sum is σ = 2812203853368. Its totient is φ = 515055650400.

The previous prime is 1287639126469. The next prime is 1287639126551. The reversal of 1287639126500 is 56219367821.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 1007173696 + 1286631952804 = 31736^2 + 1134298^2 .

It is a Harshad number since it is a multiple of its sum of digits (50).

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1287638627 + ... + 1287639626.

It is an arithmetic number, because the mean of its divisors is an integer number (117175160557).

Almost surely, 2^{1287639126500} is an apocalyptic number.

1287639126500 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1287639126500 is an abundant number, since it is smaller than the sum of its proper divisors (1524564726868).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1287639126500 is a wasteful number, since it uses less digits than its factorization.

1287639126500 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2575278272 (or 2575278260 counting only the distinct ones).

The product of its (nonzero) digits is 1088640, while the sum is 50.

The spelling of 1287639126500 in words is "one trillion, two hundred eighty-seven billion, six hundred thirty-nine million, one hundred twenty-six thousand, five hundred".