21398288020 has 24 divisors (see below), whose sum is σ = 44960424264. Its totient is φ = 8554740096.

The previous prime is 21398287961. The next prime is 21398288047. The reversal of 21398288020 is 2088289312.

It can be written as a sum of positive squares in 4 ways, for example, as 1595043844 + 19803244176 = 39938^2 + 140724^2 .

It is a congruent number.

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 7 ways as a sum of consecutive naturals, for example, 247467 + ... + 322546.

It is an arithmetic number, because the mean of its divisors is an integer number (1873351011).

Almost surely, 2^21398288020 is an apocalyptic number.

21398288020 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21398288020 is an abundant number, since it is smaller than the sum of its proper divisors (23562136244).

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

21398288020 is a wasteful number, since it uses less digits than its factorization.

21398288020 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 571899 (or 571897 counting only the distinct ones).

The product of its (nonzero) digits is 110592, while the sum is 43.

The spelling of 21398288020 in words is "twenty-one billion, three hundred ninety-eight million, two hundred eighty-eight thousand, twenty".