21376681920 has 448 divisors, whose sum is σ = 84505190400. Its totient is φ = 5041336320.

The previous prime is 21376681901. The next prime is 21376681933. The reversal of 21376681920 is 2918667312.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 3513441 + ... + 3519519.

Almost surely, 2^21376681920 is an apocalyptic number.

21376681920 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 21376681920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (42252595200).

21376681920 is an abundant number, since it is smaller than the sum of its proper divisors (63128508480).

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

21376681920 is a wasteful number, since it uses less digits than its factorization.

21376681920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6153 (or 6137 counting only the distinct ones).

The product of its (nonzero) digits is 217728, while the sum is 45.

The spelling of 21376681920 in words is "twenty-one billion, three hundred seventy-six million, six hundred eighty-one thousand, nine hundred twenty".