30818721 has 4 divisors (see below), whose sum is σ = 41091632. Its totient is φ = 20545812.

The previous prime is 30818719. The next prime is 30818761. The reversal of 30818721 is 12781803.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 12781803 = 3 ⋅4260601.

It is not a de Polignac number, because 30818721 - 2¹ = 30818719 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (30818761) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5136451 + ... + 5136456.

It is an arithmetic number, because the mean of its divisors is an integer number (10272908).

Almost surely, 2^30818721 is an apocalyptic number.

It is an amenable number.

30818721 is a deficient number, since it is larger than the sum of its proper divisors (10272911).

30818721 is a wasteful number, since it uses less digits than its factorization.

30818721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10272910.

The product of its (nonzero) digits is 2688, while the sum is 30.

The square root of 30818721 is about 5551.4611590103. The cubic root of 30818721 is about 313.5245383701.

The spelling of 30818721 in words is "thirty million, eight hundred eighteen thousand, seven hundred twenty-one".