21210421344 has 48 divisors (see below), whose sum is σ = 63631266048. Its totient is φ = 6060120192.

The previous prime is 21210421343. The next prime is 21210421381. The reversal of 21210421344 is 44312401212.

It is a tau number, because it is divible by the number of its divisors (48).

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21210421343) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 15780892 + ... + 15782235.

It is an arithmetic number, because the mean of its divisors is an integer number (1325651376).

Almost surely, 2^21210421344 is an apocalyptic number.

21210421344 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

21210421344 is an abundant number, since it is smaller than the sum of its proper divisors (42420844704).

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

21210421344 is a wasteful number, since it uses less digits than its factorization.

21210421344 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 31563147 (or 31563139 counting only the distinct ones).

The product of its (nonzero) digits is 1536, while the sum is 24.

Adding to 21210421344 its reverse (44312401212), we get a palindrome (65522822556).

The spelling of 21210421344 in words is "twenty-one billion, two hundred ten million, four hundred twenty-one thousand, three hundred forty-four".