21489394680 has 384 divisors, whose sum is σ = 82215544320. Its totient is φ = 4817387520.

The previous prime is 21489394639. The next prime is 21489394691. The reversal of 21489394680 is 8649398412.

21489394680 is a `hidden beast` number, since 2 + 148 + 9 + 39 + 468 + 0 = 666.

It is a super-3 number, since 3×21489394680³ (a number of 32 digits) contains 333 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 2462004 + ... + 2470716.

It is an arithmetic number, because the mean of its divisors is an integer number (214102980).

Almost surely, 2^21489394680 is an apocalyptic number.

21489394680 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 21489394680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (41107772160).

21489394680 is an abundant number, since it is smaller than the sum of its proper divisors (60726149640).

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

21489394680 is a wasteful number, since it uses less digits than its factorization.

21489394680 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8791 (or 8784 counting only the distinct ones).

The product of its (nonzero) digits is 2985984, while the sum is 54.

The spelling of 21489394680 in words is "twenty-one billion, four hundred eighty-nine million, three hundred ninety-four thousand, six hundred eighty".