21428499456 has 880 divisors, whose sum is σ = 83888614656. Its totient is φ = 5287182336.

The previous prime is 21428499451. The next prime is 21428499467. The reversal of 21428499456 is 65499482412.

21428499456 is a `hidden beast` number, since 2 + 142 + 8 + 49 + 9 + 456 = 666.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21428499451) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 128314285 + ... + 128314451.

Almost surely, 2^21428499456 is an apocalyptic number.

21428499456 is a gapful number since it is divisible by the number (26) 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 21428499456, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (41944307328).

21428499456 is an abundant number, since it is smaller than the sum of its proper divisors (62460115200).

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

21428499456 is a wasteful number, since it uses less digits than its factorization.

21428499456 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 236 (or 209 counting only the distinct ones).

The product of its digits is 4976640, while the sum is 54.

The spelling of 21428499456 in words is "twenty-one billion, four hundred twenty-eight million, four hundred ninety-nine thousand, four hundred fifty-six".