21683376 has 210 divisors, whose sum is σ = 74407068. Its totient is φ = 6065280.

The previous prime is 21683371. The next prime is 21683377. The reversal of 21683376 is 67338612.

It is a happy number.

It is a Smith number, since the sum of its digits (36) coincides with the sum of the digits of its prime factors.

It is a Harshad number since it is a multiple of its sum of digits (36).

Its product of digits (36288) is a multiple of the sum of its prime factors (63).

It is a self number, because there is not a number n which added to its sum of digits gives 21683376.

It is not an unprimeable number, because it can be changed into a prime (21683371) by changing a digit.

It is a polite number, since it can be written in 41 ways as a sum of consecutive naturals, for example, 1667946 + ... + 1667958.

Almost surely, 2^21683376 is an apocalyptic number.

21683376 is a gapful number since it is divisible by the number (26) 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 21683376, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (37203534).

21683376 is an abundant number, since it is smaller than the sum of its proper divisors (52723692).

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

21683376 is a wasteful number, since it uses less digits than its factorization.

21683376 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 63 (or 29 counting only the distinct ones).

The product of its digits is 36288, while the sum is 36.

The square root of 21683376 is about 4656.5412056590. The cubic root of 21683376 is about 278.8532006088.

The spelling of 21683376 in words is "twenty-one million, six hundred eighty-three thousand, three hundred seventy-six".