287906640 has 160 divisors (see below), whose sum is σ = 1064503296. Its totient is φ = 62937600.

The previous prime is 287906627. The next prime is 287906651. The reversal of 287906640 is 46609782.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is a junction number, because it is equal to n+sod(n) for n = 287906592 and 287906601.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 34915 + ... + 42365.

Almost surely, 2^287906640 is an apocalyptic number.

287906640 is a gapful number since it is divisible by the number (20) 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 287906640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (532251648).

287906640 is an abundant number, since it is smaller than the sum of its proper divisors (776596656).

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

287906640 is a wasteful number, since it uses less digits than its factorization.

287906640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7497 (or 7491 counting only the distinct ones).

The product of its (nonzero) digits is 145152, while the sum is 42.

The square root of 287906640 is about 16967.8118801453. The cubic root of 287906640 is about 660.3140837502.

The spelling of 287906640 in words is "two hundred eighty-seven million, nine hundred six thousand, six hundred forty".