21930480 has 320 divisors, whose sum is σ = 89994240. Its totient is φ = 4838400.

The previous prime is 21930463. The next prime is 21930497. The reversal of 21930480 is 8403912.

It is an interprime number because it is at equal distance from previous prime (21930463) and next prime (21930497).

It is a Harshad number since it is a multiple of its sum of digits (27).

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, 308845 + ... + 308915.

It is an arithmetic number, because the mean of its divisors is an integer number (281232).

Almost surely, 2^21930480 is an apocalyptic number.

21930480 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 21930480, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (44997120).

21930480 is an abundant number, since it is smaller than the sum of its proper divisors (68063760).

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

21930480 is a wasteful number, since it uses less digits than its factorization.

21930480 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 117 (or 105 counting only the distinct ones).

The product of its (nonzero) digits is 1728, while the sum is 27.

The square root of 21930480 is about 4682.9990390774. Note that the first 3 decimals coincide. The cubic root of 21930480 is about 279.9084734864.

The spelling of 21930480 in words is "twenty-one million, nine hundred thirty thousand, four hundred eighty".