30821881 has 4 divisors (see below), whose sum is σ = 31256064. Its totient is φ = 30387700.

The previous prime is 30821837. The next prime is 30821887. The reversal of 30821881 is 18812803.

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.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-30821881 is a prime.

It is a super-2 number, since 2×30821881² = 1899976696756322, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (30821887) 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, 216985 + ... + 217126.

It is an arithmetic number, because the mean of its divisors is an integer number (7814016).

Almost surely, 2^30821881 is an apocalyptic number.

It is an amenable number.

30821881 is a deficient number, since it is larger than the sum of its proper divisors (434183).

30821881 is an equidigital number, since it uses as much as digits as its factorization.

30821881 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 434182.

The product of its (nonzero) digits is 3072, while the sum is 31.

The square root of 30821881 is about 5551.7457614700. The cubic root of 30821881 is about 313.5352537584.

The spelling of 30821881 in words is "thirty million, eight hundred twenty-one thousand, eight hundred eighty-one".