30321720 has 384 divisors, whose sum is σ = 125798400. Its totient is φ = 6220800.

The previous prime is 30321713. The next prime is 30321737. The reversal of 30321720 is 2712303.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a junction number, because it is equal to n+sod(n) for n = 30321693 and 30321702.

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 95 ways as a sum of consecutive naturals, for example, 978105 + ... + 978135.

It is an arithmetic number, because the mean of its divisors is an integer number (327600).

Almost surely, 2^30321720 is an apocalyptic number.

30321720 is a gapful number since it is divisible by the number (30) 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 30321720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (62899200).

30321720 is an abundant number, since it is smaller than the sum of its proper divisors (95476680).

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

30321720 is a wasteful number, since it uses less digits than its factorization.

30321720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 91 (or 84 counting only the distinct ones).

The product of its (nonzero) digits is 252, while the sum is 18.

The square root of 30321720 is about 5506.5161399927. The cubic root of 30321720 is about 311.8300356326.

The spelling of 30321720 in words is "thirty million, three hundred twenty-one thousand, seven hundred twenty".