21544590620 has 96 divisors (see below), whose sum is σ = 56084192640. Its totient is φ = 6782607360.

The previous prime is 21544590619. The next prime is 21544590631. The reversal of 21544590620 is 2609544512.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 12815 + ... + 207974.

It is an arithmetic number, because the mean of its divisors is an integer number (584210340).

Almost surely, 2^21544590620 is an apocalyptic number.

21544590620 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 21544590620, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28042096320).

21544590620 is an abundant number, since it is smaller than the sum of its proper divisors (34539602020).

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

21544590620 is a wasteful number, since it uses less digits than its factorization.

21544590620 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 220863 (or 220861 counting only the distinct ones).

The product of its (nonzero) digits is 86400, while the sum is 38.

The spelling of 21544590620 in words is "twenty-one billion, five hundred forty-four million, five hundred ninety thousand, six hundred twenty".