30421991 has 2 divisors, whose sum is σ = 30421992. Its totient is φ = 30421990.

The previous prime is 30421987. The next prime is 30422003. The reversal of 30421991 is 19912403.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 30421991 - 2² = 30421987 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (30421901) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15210995 + 15210996.

It is an arithmetic number, because the mean of its divisors is an integer number (15210996).

Almost surely, 2^30421991 is an apocalyptic number.

30421991 is a deficient number, since it is larger than the sum of its proper divisors (1).

30421991 is an equidigital number, since it uses as much as digits as its factorization.

30421991 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1944, while the sum is 29.

The square root of 30421991 is about 5515.6133838405. The cubic root of 30421991 is about 312.1733880377.

The spelling of 30421991 in words is "thirty million, four hundred twenty-one thousand, nine hundred ninety-one".