21403928567844 has 27 divisors (see below), whose sum is σ = 54104445158673. Its totient is φ = 7134633603072.

The previous prime is 21403928567837. The next prime is 21403928567867. The reversal of 21403928567844 is 44876582930412.

The square root of 21403928567844 is 4626438.

It is a perfect power (a square), and thus also a powerful number.

21403928567844 is a `hidden beast` number, since 2 + 1 + 4 + 0 + 3 + 9 + 28 + 567 + 8 + 44 = 666.

It can be written as a sum of positive squares in only one way, i.e., 3992603422500 + 17411325145344 = 1998150^2 + 4172688^2 .

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 27373092 + ... + 28144164.

It is a 1-persistent number, because it is pandigital, but 2⋅21403928567844 = 42807857135688 is not.

Almost surely, 2^{21403928567844} is an apocalyptic number.

21403928567844 is the 4626438-th square number.

It is an amenable number.

21403928567844 is an abundant number, since it is smaller than the sum of its proper divisors (32700516590829).

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

21403928567844 is an frugal number, since it uses more digits than its factorization.

21403928567844 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1542156 (or 771078 counting only the distinct ones).

The product of its (nonzero) digits is 92897280, while the sum is 63.

The spelling of 21403928567844 in words is "twenty-one trillion, four hundred three billion, nine hundred twenty-eight million, five hundred sixty-seven thousand, eight hundred forty-four".