1399607640 has 128 divisors (see below), whose sum is σ = 4910976000. Its totient is φ = 353579904.

The previous prime is 1399607639. The next prime is 1399607647. The reversal of 1399607640 is 467069931.

1399607640 is a `hidden beast` number, since 1 + 39 + 9 + 607 + 6 + 4 + 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 not an unprimeable number, because it can be changed into a prime (1399607647) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 13584 + ... + 54623.

It is an arithmetic number, because the mean of its divisors is an integer number (38367000).

Almost surely, 2^1399607640 is an apocalyptic number.

1399607640 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 1399607640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2455488000).

1399607640 is an abundant number, since it is smaller than the sum of its proper divisors (3511368360).

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

1399607640 is a wasteful number, since it uses less digits than its factorization.

1399607640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 68246 (or 68236 counting only the distinct ones).

The product of its (nonzero) digits is 244944, while the sum is 45.

The square root of 1399607640 is about 37411.3303692879. The cubic root of 1399607640 is about 1118.5844254614.

The spelling of 1399607640 in words is "one billion, three hundred ninety-nine million, six hundred seven thousand, six hundred forty".