21434232440 has 64 divisors (see below), whose sum is σ = 49370873760. Its totient is φ = 8371883520.

The previous prime is 21434232433. The next prime is 21434232503. The reversal of 21434232440 is 4423243412.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 423362 + ... + 471278.

Almost surely, 2^21434232440 is an apocalyptic number.

21434232440 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21434232440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24685436880).

21434232440 is an abundant number, since it is smaller than the sum of its proper divisors (27936641320).

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

21434232440 is a wasteful number, since it uses less digits than its factorization.

21434232440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 48192 (or 48188 counting only the distinct ones).

The product of its (nonzero) digits is 18432, while the sum is 29.

Adding to 21434232440 its reverse (4423243412), we get a palindrome (25857475852).

The spelling of 21434232440 in words is "twenty-one billion, four hundred thirty-four million, two hundred thirty-two thousand, four hundred forty".