393992640 has 224 divisors, whose sum is σ = 1435729920. Its totient is φ = 101606400.

The previous prime is 393992633. The next prime is 393992647. The reversal of 393992640 is 46299393.

It is an interprime number because it is at equal distance from previous prime (393992633) and next prime (393992647).

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (393992647) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 267105 + ... + 268575.

Almost surely, 2^393992640 is an apocalyptic number.

393992640 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 393992640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (717864960).

393992640 is an abundant number, since it is smaller than the sum of its proper divisors (1041737280).

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

393992640 is a wasteful number, since it uses less digits than its factorization.

393992640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1528 (or 1512 counting only the distinct ones).

The product of its (nonzero) digits is 314928, while the sum is 45.

The square root of 393992640 is about 19849.2478446917. The cubic root of 393992640 is about 733.0991281482.

The spelling of 393992640 in words is "three hundred ninety-three million, nine hundred ninety-two thousand, six hundred forty".