22009991 has 2 divisors, whose sum is σ = 22009992. Its totient is φ = 22009990.

The previous prime is 22009973. The next prime is 22010003. The reversal of 22009991 is 19990022.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 22009991 - 2¹⁰ = 22008967 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (22009921) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 11004995 + 11004996.

It is an arithmetic number, because the mean of its divisors is an integer number (11004996).

Almost surely, 2^22009991 is an apocalyptic number.

22009991 is a deficient number, since it is larger than the sum of its proper divisors (1).

22009991 is an equidigital number, since it uses as much as digits as its factorization.

22009991 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2916, while the sum is 32.

The square root of 22009991 is about 4691.4806831106. The cubic root of 22009991 is about 280.2463435779.

The spelling of 22009991 in words is "twenty-two million, nine thousand, nine hundred ninety-one".