21245341440 has 72 divisors (see below), whose sum is σ = 67852321488. Its totient is φ = 5665423360.

The previous prime is 21245341393. The next prime is 21245341441. The reversal of 21245341440 is 4414354212.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a junction number, because it is equal to n+sod(n) for n = 21245341398 and 21245341407.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21245341441) 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, 2762481 + ... + 2770160.

It is an arithmetic number, because the mean of its divisors is an integer number (942393354).

Almost surely, 2^21245341440 is an apocalyptic number.

21245341440 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21245341440 is an abundant number, since it is smaller than the sum of its proper divisors (46606980048).

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

21245341440 is an equidigital number, since it uses as much as digits as its factorization.

21245341440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5532665 (or 5532651 counting only the distinct ones).

The product of its (nonzero) digits is 15360, while the sum is 30.

Adding to 21245341440 its reverse (4414354212), we get a palindrome (25659695652).

The spelling of 21245341440 in words is "twenty-one billion, two hundred forty-five million, three hundred forty-one thousand, four hundred forty".