21230221091 has 2 divisors, whose sum is σ = 21230221092. Its totient is φ = 21230221090.

The previous prime is 21230221087. The next prime is 21230221147. The reversal of 21230221091 is 19012203212.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21230221091 - 2² = 21230221087 is a prime.

It is not a weakly prime, because it can be changed into another prime (21230221291) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10615110545 + 10615110546.

It is an arithmetic number, because the mean of its divisors is an integer number (10615110546).

Almost surely, 2^21230221091 is an apocalyptic number.

21230221091 is a deficient number, since it is larger than the sum of its proper divisors (1).

21230221091 is an equidigital number, since it uses as much as digits as its factorization.

21230221091 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 432, while the sum is 23.

The spelling of 21230221091 in words is "twenty-one billion, two hundred thirty million, two hundred twenty-one thousand, ninety-one".