21304400440 has 32 divisors (see below), whose sum is σ = 50019029280. Its totient is φ = 8151248512.

The previous prime is 21304400437. The next prime is 21304400483. The reversal of 21304400440 is 4400440312.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 11577559 + ... + 11579398.

It is an arithmetic number, because the mean of its divisors is an integer number (1563094665).

Almost surely, 2^21304400440 is an apocalyptic number.

21304400440 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21304400440 is an abundant number, since it is smaller than the sum of its proper divisors (28714628840).

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

21304400440 is a wasteful number, since it uses less digits than its factorization.

21304400440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 23156991 (or 23156987 counting only the distinct ones).

The product of its (nonzero) digits is 1536, while the sum is 22.

Adding to 21304400440 its reverse (4400440312), we get a palindrome (25704840752).

The spelling of 21304400440 in words is "twenty-one billion, three hundred four million, four hundred thousand, four hundred forty".