393645440 has 64 divisors (see below), whose sum is σ = 971464320. Its totient is φ = 152371200.

The previous prime is 393645433. The next prime is 393645481. The reversal of 393645440 is 44546393.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (64).

It is a super-3 number, since 3×393645440³ (a number of 27 digits) contains 333 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 393645394 and 393645403.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 9920 + ... + 29760.

It is an arithmetic number, because the mean of its divisors is an integer number (15179130).

Almost surely, 2^393645440 is an apocalyptic number.

It is a pronic number, being equal to 19840×19841.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 393645440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (485732160).

393645440 is an abundant number, since it is smaller than the sum of its proper divisors (577818880).

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

393645440 is a wasteful number, since it uses less digits than its factorization.

393645440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19891 (or 19879 counting only the distinct ones).

The product of its (nonzero) digits is 155520, while the sum is 38.

The square root of 393645440 is about 19840.4999936998. The cubic root of 393645440 is about 732.8837207221.

The spelling of 393645440 in words is "three hundred ninety-three million, six hundred forty-five thousand, four hundred forty".