1391404644540 has 144 divisors (see below), whose sum is σ = 4274724400128. Its totient is φ = 366289402752.

The previous prime is 1391404644499. The next prime is 1391404644547. The reversal of 1391404644540 is 454464041931.

1391404644540 is a `hidden beast` number, since 1 + 3 + 9 + 1 + 40 + 4 + 64 + 4 + 540 = 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 (1391404644547) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 19790289 + ... + 19860471.

It is an arithmetic number, because the mean of its divisors is an integer number (29685586112).

Almost surely, 2^{1391404644540} is an apocalyptic number.

1391404644540 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 1391404644540, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2137362200064).

1391404644540 is an abundant number, since it is smaller than the sum of its proper divisors (2883319755588).

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

1391404644540 is a wasteful number, since it uses less digits than its factorization.

1391404644540 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 71608 (or 71603 counting only the distinct ones).

The product of its (nonzero) digits is 829440, while the sum is 45.

The spelling of 1391404644540 in words is "one trillion, three hundred ninety-one billion, four hundred four million, six hundred forty-four thousand, five hundred forty".