221201430991 has 2 divisors, whose sum is σ = 221201430992. Its totient is φ = 221201430990.

The previous prime is 221201430959. The next prime is 221201431051. The reversal of 221201430991 is 199034102122.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 221201430991 - 2⁵ = 221201430959 is a prime.

It is a super-2 number, since 2×221201430991² (a number of 23 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (221201430091) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 110600715495 + 110600715496.

It is an arithmetic number, because the mean of its divisors is an integer number (110600715496).

Almost surely, 2^221201430991 is an apocalyptic number.

221201430991 is a deficient number, since it is larger than the sum of its proper divisors (1).

221201430991 is an equidigital number, since it uses as much as digits as its factorization.

221201430991 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 7776, while the sum is 34.

The spelling of 221201430991 in words is "two hundred twenty-one billion, two hundred one million, four hundred thirty thousand, nine hundred ninety-one".