390243840 has 480 divisors, whose sum is σ = 1561801824. Its totient is φ = 82575360.

The previous prime is 390243811. The next prime is 390243851. The reversal of 390243840 is 48342093.

It is a tau number, because it is divible by the number of its divisors (480).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 6397410 + ... + 6397470.

Almost surely, 2^390243840 is an apocalyptic number.

390243840 is a gapful number since it is divisible by the number (30) 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 390243840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (780900912).

390243840 is an abundant number, since it is smaller than the sum of its proper divisors (1171557984).

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

390243840 is a wasteful number, since it uses less digits than its factorization.

390243840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 118 (or 95 counting only the distinct ones).

The product of its (nonzero) digits is 20736, while the sum is 33.

The square root of 390243840 is about 19754.5903526244. The cubic root of 390243840 is about 730.7665932087.

The spelling of 390243840 in words is "three hundred ninety million, two hundred forty-three thousand, eight hundred forty".