287978640 has 80 divisors (see below), whose sum is σ = 945260928. Its totient is φ = 72275968.

The previous prime is 287978633. The next prime is 287978651. The reversal of 287978640 is 46879782.

It is a tau number, because it is divible by the number of its divisors (80).

It is a Harshad number since it is a multiple of its sum of digits (51).

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 31212 + ... + 39371.

Almost surely, 2^287978640 is an apocalyptic number.

287978640 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

287978640 is an abundant number, since it is smaller than the sum of its proper divisors (657282288).

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

287978640 is a wasteful number, since it uses less digits than its factorization.

287978640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 70616 (or 70610 counting only the distinct ones).

The product of its (nonzero) digits is 1354752, while the sum is 51.

The square root of 287978640 is about 16969.9334117727. The cubic root of 287978640 is about 660.3691231794.

The spelling of 287978640 in words is "two hundred eighty-seven million, nine hundred seventy-eight thousand, six hundred forty".