21485919840 has 288 divisors, whose sum is σ = 85888905984. Its totient is φ = 4464552960.

The previous prime is 21485919839. The next prime is 21485919877. The reversal of 21485919840 is 4891958412.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 217197 + ... + 300243.

It is an arithmetic number, because the mean of its divisors is an integer number (298225368).

Almost surely, 2^21485919840 is an apocalyptic number.

21485919840 is a gapful number since it is divisible by the number (20) 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 21485919840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (42944452992).

21485919840 is an abundant number, since it is smaller than the sum of its proper divisors (64402986144).

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

21485919840 is a wasteful number, since it uses less digits than its factorization.

21485919840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 83090 (or 83075 counting only the distinct ones).

The product of its (nonzero) digits is 829440, while the sum is 51.

The spelling of 21485919840 in words is "twenty-one billion, four hundred eighty-five million, nine hundred nineteen thousand, eight hundred forty".