21345320443440 has 120 divisors (see below), whose sum is σ = 76973839274160. Its totient is φ = 4878930384384.

The previous prime is 21345320443439. The next prime is 21345320443477. The reversal of 21345320443440 is 4434402354312.

It is a tau number, because it is divible by the number of its divisors (120).

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 907527375 + ... + 907550894.

It is an arithmetic number, because the mean of its divisors is an integer number (641448660618).

Almost surely, 2^{21345320443440} is an apocalyptic number.

21345320443440 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21345320443440 is an abundant number, since it is smaller than the sum of its proper divisors (55628518830720).

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

21345320443440 is a wasteful number, since it uses less digits than its factorization.

21345320443440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1815078299 (or 1815078286 counting only the distinct ones).

The product of its (nonzero) digits is 552960, while the sum is 39.

Adding to 21345320443440 its reverse (4434402354312), we get a palindrome (25779722797752).

The spelling of 21345320443440 in words is "twenty-one trillion, three hundred forty-five billion, three hundred twenty million, four hundred forty-three thousand, four hundred forty".