1287213720 has 256 divisors, whose sum is σ = 4424112000. Its totient is φ = 297271296.

The previous prime is 1287213659. The next prime is 1287213727. The reversal of 1287213720 is 273127821.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1287213727) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 1673496 + ... + 1674264.

Almost surely, 2^1287213720 is an apocalyptic number.

1287213720 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 1287213720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2212056000).

1287213720 is an abundant number, since it is smaller than the sum of its proper divisors (3136898280).

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

1287213720 is a wasteful number, since it uses less digits than its factorization.

1287213720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 862 (or 858 counting only the distinct ones).

The product of its (nonzero) digits is 9408, while the sum is 33.

The square root of 1287213720 is about 35877.7607996932. The cubic root of 1287213720 is about 1087.8029194464.

The spelling of 1287213720 in words is "one billion, two hundred eighty-seven million, two hundred thirteen thousand, seven hundred twenty".