21450203904 has 72 divisors (see below), whose sum is σ = 57180589312. Its totient is φ = 7138575360.

The previous prime is 21450203867. The next prime is 21450203911. The reversal of 21450203904 is 40930205412.

It is a super-2 number, since 2×21450203904² (a number of 21 digits) contains 22 as substring.

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 7 ways as a sum of consecutive naturals, for example, 462477 + ... + 506739.

Almost surely, 2^21450203904 is an apocalyptic number.

21450203904 is a gapful number since it is divisible by the number (24) 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 21450203904, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28590294656).

21450203904 is an abundant number, since it is smaller than the sum of its proper divisors (35730385408).

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

21450203904 is an equidigital number, since it uses as much as digits as its factorization.

21450203904 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 44913 (or 44899 counting only the distinct ones).

The product of its (nonzero) digits is 8640, while the sum is 30.

The spelling of 21450203904 in words is "twenty-one billion, four hundred fifty million, two hundred three thousand, nine hundred four".