21400340440 has 16 divisors (see below), whose sum is σ = 48150766080. Its totient is φ = 8560136160.

The previous prime is 21400340431. The next prime is 21400340447. The reversal of 21400340440 is 4404300412.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21400340447) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 267504216 + ... + 267504295.

It is an arithmetic number, because the mean of its divisors is an integer number (3009422880).

Almost surely, 2^21400340440 is an apocalyptic number.

21400340440 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21400340440 is an abundant number, since it is smaller than the sum of its proper divisors (26750425640).

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

21400340440 is a wasteful number, since it uses less digits than its factorization.

21400340440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 535008522 (or 535008518 counting only the distinct ones).

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

Adding to 21400340440 its reverse (4404300412), we get a palindrome (25804640852).

The spelling of 21400340440 in words is "twenty-one billion, four hundred million, three hundred forty thousand, four hundred forty".