30219821 has 2 divisors, whose sum is σ = 30219822. Its totient is φ = 30219820.

The previous prime is 30219817. The next prime is 30219853. The reversal of 30219821 is 12891203.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 29278921 + 940900 = 5411^2 + 970^2 .

It is a cyclic number.

It is not a de Polignac number, because 30219821 - 2² = 30219817 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (30210821) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15109910 + 15109911.

It is an arithmetic number, because the mean of its divisors is an integer number (15109911).

Almost surely, 2^30219821 is an apocalyptic number.

It is an amenable number.

30219821 is a deficient number, since it is larger than the sum of its proper divisors (1).

30219821 is an equidigital number, since it uses as much as digits as its factorization.

30219821 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 864, while the sum is 26.

The square root of 30219821 is about 5497.2557699274. The cubic root of 30219821 is about 311.4803321869.

The spelling of 30219821 in words is "thirty million, two hundred nineteen thousand, eight hundred twenty-one".