22191881 has 2 divisors, whose sum is σ = 22191882. Its totient is φ = 22191880.

The previous prime is 22191833. The next prime is 22191887. The reversal of 22191881 is 18819122.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 13542400 + 8649481 = 3680^2 + 2941^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-22191881 is a prime.

It is a super-2 number, since 2×22191881² = 984959164636322, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (22191887) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 11095940 + 11095941.

It is an arithmetic number, because the mean of its divisors is an integer number (11095941).

Almost surely, 2^22191881 is an apocalyptic number.

It is an amenable number.

22191881 is a deficient number, since it is larger than the sum of its proper divisors (1).

22191881 is an equidigital number, since it uses as much as digits as its factorization.

22191881 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2304, while the sum is 32.

The square root of 22191881 is about 4710.8259360753. The cubic root of 22191881 is about 281.0162095992.

The spelling of 22191881 in words is "twenty-two million, one hundred ninety-one thousand, eight hundred eighty-one".