1397836440 has 640 divisors, whose sum is σ = 6322821120. Its totient is φ = 267494400.

The previous prime is 1397836439. The next prime is 1397836459. The reversal of 1397836440 is 446387931.

1397836440 is a `hidden beast` number, since 139 + 78 + 3 + 6 + 440 = 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 (13) of ones.

It is a polite number, since it can be written in 159 ways as a sum of consecutive naturals, for example, 3243025 + ... + 3243455.

It is an arithmetic number, because the mean of its divisors is an integer number (9879408).

Almost surely, 2^1397836440 is an apocalyptic number.

1397836440 is a gapful number since it is divisible by the number (10) 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 1397836440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3161410560).

1397836440 is an abundant number, since it is smaller than the sum of its proper divisors (4924984680).

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

1397836440 is a wasteful number, since it uses less digits than its factorization.

1397836440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 485 (or 472 counting only the distinct ones).

The product of its (nonzero) digits is 435456, while the sum is 45.

The square root of 1397836440 is about 37387.6509024036. The cubic root of 1397836440 is about 1118.1123710046.

The spelling of 1397836440 in words is "one billion, three hundred ninety-seven million, eight hundred thirty-six thousand, four hundred forty".