21424967780 has 24 divisors (see below), whose sum is σ = 45730015800. Its totient is φ = 8429495040.

The previous prime is 21424967747. The next prime is 21424967789. The reversal of 21424967780 is 8776942412.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 1974202624 + 19450765156 = 44432^2 + 139466^2 .

It is not an unprimeable number, because it can be changed into a prime (21424967789) 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, 8779505 + ... + 8781944.

It is an arithmetic number, because the mean of its divisors is an integer number (1905417325).

Almost surely, 2^21424967780 is an apocalyptic number.

21424967780 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21424967780 is an abundant number, since it is smaller than the sum of its proper divisors (24305048020).

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

21424967780 is a wasteful number, since it uses less digits than its factorization.

21424967780 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17561519 (or 17561517 counting only the distinct ones).

The product of its (nonzero) digits is 1354752, while the sum is 50.

The spelling of 21424967780 in words is "twenty-one billion, four hundred twenty-four million, nine hundred sixty-seven thousand, seven hundred eighty".