30381721 has 4 divisors (see below), whose sum is σ = 30879844. Its totient is φ = 29883600.

The previous prime is 30381719. The next prime is 30381727. The reversal of 30381721 is 12718303.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 9120400 + 21261321 = 3020^2 + 4611^2 .

It is a cyclic number.

It is not a de Polignac number, because 30381721 - 2¹ = 30381719 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (30381727) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 248970 + ... + 249091.

It is an arithmetic number, because the mean of its divisors is an integer number (7719961).

Almost surely, 2^30381721 is an apocalyptic number.

It is an amenable number.

30381721 is a deficient number, since it is larger than the sum of its proper divisors (498123).

30381721 is an equidigital number, since it uses as much as digits as its factorization.

30381721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 498122.

The product of its (nonzero) digits is 1008, while the sum is 25.

The square root of 30381721 is about 5511.9616290392. The cubic root of 30381721 is about 312.0355845070.

The spelling of 30381721 in words is "thirty million, three hundred eighty-one thousand, seven hundred twenty-one".