30720331 has 2 divisors, whose sum is σ = 30720332. Its totient is φ = 30720330.

The previous prime is 30720307. The next prime is 30720401. The reversal of 30720331 is 13302703.

It is a weak prime.

It is an emirp because it is prime and its reverse (13302703) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 30720331 - 2⁵ = 30720299 is a prime.

It is a super-2 number, since 2×30720331² = 1887477473499122, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 30720299 and 30720308.

It is not a weakly prime, because it can be changed into another prime (30720031) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15360165 + 15360166.

It is an arithmetic number, because the mean of its divisors is an integer number (15360166).

Almost surely, 2^30720331 is an apocalyptic number.

30720331 is a deficient number, since it is larger than the sum of its proper divisors (1).

30720331 is an equidigital number, since it uses as much as digits as its factorization.

30720331 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 378, while the sum is 19.

The square root of 30720331 is about 5542.5924439742. The cubic root of 30720331 is about 313.1905361343.

The spelling of 30720331 in words is "thirty million, seven hundred twenty thousand, three hundred thirty-one".