21428835840 has 120 divisors (see below), whose sum is σ = 74214165168. Its totient is φ = 5714350080.

The previous prime is 21428835811. The next prime is 21428835871. The reversal of 21428835840 is 4853882412.

21428835840 is a `hidden beast` number, since 2 + 14 + 288 + 358 + 4 + 0 = 666.

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

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 441996 + ... + 488075.

Almost surely, 2^21428835840 is an apocalyptic number.

21428835840 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21428835840 is an abundant number, since it is smaller than the sum of its proper divisors (52785329328).

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

21428835840 is an equidigital number, since it uses as much as digits as its factorization.

21428835840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 930100 (or 930081 counting only the distinct ones).

The product of its (nonzero) digits is 491520, while the sum is 45.

The spelling of 21428835840 in words is "twenty-one billion, four hundred twenty-eight million, eight hundred thirty-five thousand, eight hundred forty".