1921383653640 has 64 divisors (see below), whose sum is σ = 6288164688960. Its totient is φ = 465789976320.

The previous prime is 1921383653509. The next prime is 1921383653647. The reversal of 1921383653640 is 463563831291.

It is a happy number.

It is not an unprimeable number, because it can be changed into a prime (1921383653647) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 727795519 + ... + 727798158.

It is an arithmetic number, because the mean of its divisors is an integer number (98252573265).

Almost surely, 2^{1921383653640} is an apocalyptic number.

1921383653640 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1921383653640 is an abundant number, since it is smaller than the sum of its proper divisors (4366781035320).

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

1921383653640 is a wasteful number, since it uses less digits than its factorization.

1921383653640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1455593702 (or 1455593698 counting only the distinct ones).

The product of its (nonzero) digits is 2799360, while the sum is 51.

The spelling of 1921383653640 in words is "one trillion, nine hundred twenty-one billion, three hundred eighty-three million, six hundred fifty-three thousand, six hundred forty".