21403279842 has 128 divisors (see below), whose sum is σ = 51852607488. Its totient is φ = 5760417600.

The previous prime is 21403279841. The next prime is 21403279883. The reversal of 21403279842 is 24897230412.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is a junction number, because it is equal to n+sod(n) for n = 21403279794 and 21403279803.

It is not an unprimeable number, because it can be changed into a prime (21403279841) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 24129523 + ... + 24130409.

It is an arithmetic number, because the mean of its divisors is an integer number (405098496).

Almost surely, 2^21403279842 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21403279842, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25926303744).

21403279842 is an abundant number, since it is smaller than the sum of its proper divisors (30449327646).

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

21403279842 is a wasteful number, since it uses less digits than its factorization.

21403279842 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1404.

The product of its (nonzero) digits is 193536, while the sum is 42.

The spelling of 21403279842 in words is "twenty-one billion, four hundred three million, two hundred seventy-nine thousand, eight hundred forty-two".