397835640 has 96 divisors (see below), whose sum is σ = 1296051120. Its totient is φ = 105836544.

The previous prime is 397835639. The next prime is 397835651. The reversal of 397835640 is 46538793.

397835640 is a `hidden beast` number, since 3 + 9 + 7 + 83 + 564 + 0 = 666.

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

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 187224 + ... + 189336.

Almost surely, 2^397835640 is an apocalyptic number.

397835640 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 397835640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (648025560).

397835640 is an abundant number, since it is smaller than the sum of its proper divisors (898215480).

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

397835640 is a wasteful number, since it uses less digits than its factorization.

397835640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2653 (or 2646 counting only the distinct ones).

The product of its (nonzero) digits is 544320, while the sum is 45.

The square root of 397835640 is about 19945.8176067064. The cubic root of 397835640 is about 735.4749671948.

The spelling of 397835640 in words is "three hundred ninety-seven million, eight hundred thirty-five thousand, six hundred forty".