1921513680 has 60 divisors (see below), whose sum is σ = 6453085860. Its totient is φ = 512403456.

The previous prime is 1921513673. The next prime is 1921513709. The reversal of 1921513680 is 863151291.

It can be written as a sum of positive squares in 2 ways, for example, as 1260818064 + 660695616 = 35508^2 + 25704^2 .

It is a tau number, because it is divible by the number of its divisors (60).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1333665 + ... + 1335104.

It is an arithmetic number, because the mean of its divisors is an integer number (107551431).

Almost surely, 2^1921513680 is an apocalyptic number.

1921513680 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1921513680 is an abundant number, since it is smaller than the sum of its proper divisors (4531572180).

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

1921513680 is a wasteful number, since it uses less digits than its factorization.

1921513680 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2668788 (or 2668779 counting only the distinct ones).

The product of its (nonzero) digits is 12960, while the sum is 36.

The square root of 1921513680 is about 43835.0736283173. The cubic root of 1921513680 is about 1243.2195385092.

The spelling of 1921513680 in words is "one billion, nine hundred twenty-one million, five hundred thirteen thousand, six hundred eighty".