397785997440 has 640 divisors, whose sum is σ = 1619877132720. Its totient is φ = 92154101760.

The previous prime is 397785997429. The next prime is 397785997507. The reversal of 397785997440 is 44799587793.

397785997440 is a `hidden beast` number, since 3 + 97 + 7 + 8 + 5 + 9 + 97 + 440 = 666.

It can be written as a sum of positive squares in 8 ways, for example, as 168605499456 + 229180497984 = 410616^2 + 478728^2 .

It is a tau number, because it is divible by the number of its divisors (640).

It is a Harshad number since it is a multiple of its sum of digits (72).

It is an unprimeable number.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 11439280 + ... + 11474000.

Almost surely, 2^397785997440 is an apocalyptic number.

397785997440 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 397785997440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (809938566360).

397785997440 is an abundant number, since it is smaller than the sum of its proper divisors (1222091135280).

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

397785997440 is a wasteful number, since it uses less digits than its factorization.

397785997440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 34782 (or 34761 counting only the distinct ones).

The product of its (nonzero) digits is 480090240, while the sum is 72.

The spelling of 397785997440 in words is "three hundred ninety-seven billion, seven hundred eighty-five million, nine hundred ninety-seven thousand, four hundred forty".