21290969680 has 80 divisors (see below), whose sum is σ = 50191033104. Its totient is φ = 8398438400.

The previous prime is 21290969671. The next prime is 21290969683. The reversal of 21290969680 is 8696909212.

It can be written as a sum of positive squares in 8 ways, for example, as 2303232064 + 18987737616 = 47992^2 + 137796^2 .

It is a tau number, because it is divible by the number of its divisors (80).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21290969683) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2071434 + ... + 2081686.

Almost surely, 2^21290969680 is an apocalyptic number.

21290969680 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 21290969680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25095516552).

21290969680 is an abundant number, since it is smaller than the sum of its proper divisors (28900063424).

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

21290969680 is a wasteful number, since it uses less digits than its factorization.

21290969680 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10624 (or 10618 counting only the distinct ones).

The product of its (nonzero) digits is 839808, while the sum is 52.

The spelling of 21290969680 in words is "twenty-one billion, two hundred ninety million, nine hundred sixty-nine thousand, six hundred eighty".