1287205920 has 1152 divisors, whose sum is σ = 6340239360. Its totient is φ = 228925440.

The previous prime is 1287205889. The next prime is 1287205991. The reversal of 1287205920 is 295027821.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 191 ways as a sum of consecutive naturals, for example, 27387337 + ... + 27387383.

It is an arithmetic number, because the mean of its divisors is an integer number (5503680).

Almost surely, 2^1287205920 is an apocalyptic number.

1287205920 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1287205920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3170119680).

1287205920 is an abundant number, since it is smaller than the sum of its proper divisors (5053033440).

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

1287205920 is a wasteful number, since it uses less digits than its factorization.

1287205920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 118 (or 107 counting only the distinct ones).

The product of its (nonzero) digits is 20160, while the sum is 36.

The square root of 1287205920 is about 35877.6520970924. The cubic root of 1287205920 is about 1087.8007222252.

The spelling of 1287205920 in words is "one billion, two hundred eighty-seven million, two hundred five thousand, nine hundred twenty".