21434840756 has 24 divisors (see below), whose sum is σ = 44252576256. Its totient is φ = 8890025760.

The previous prime is 21434840741. The next prime is 21434840761. The reversal of 21434840756 is 65704843412.

It is a happy number.

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, 12346391 + ... + 12348126.

It is an arithmetic number, because the mean of its divisors is an integer number (1843857344).

Almost surely, 2^21434840756 is an apocalyptic number.

It is an amenable number.

21434840756 is an abundant number, since it is smaller than the sum of its proper divisors (22817735500).

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

21434840756 is a wasteful number, since it uses less digits than its factorization.

21434840756 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 24694559 (or 24694557 counting only the distinct ones).

The product of its (nonzero) digits is 645120, while the sum is 44.

The spelling of 21434840756 in words is "twenty-one billion, four hundred thirty-four million, eight hundred forty thousand, seven hundred fifty-six".