21999981149 has 2 divisors, whose sum is σ = 21999981150. Its totient is φ = 21999981148.

The previous prime is 21999981121. The next prime is 21999981161. The reversal of 21999981149 is 94118999912.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 13021092100 + 8978889049 = 114110^2 + 94757^2 .

It is a cyclic number.

It is not a de Polignac number, because 21999981149 - 2²⁴ = 21983203933 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 21999981091 and 21999981100.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21999981449) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10999990574 + 10999990575.

It is an arithmetic number, because the mean of its divisors is an integer number (10999990575).

Almost surely, 2^21999981149 is an apocalyptic number.

It is an amenable number.

21999981149 is a deficient number, since it is larger than the sum of its proper divisors (1).

21999981149 is an equidigital number, since it uses as much as digits as its factorization.

21999981149 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3779136, while the sum is 62.

The spelling of 21999981149 in words is "twenty-one billion, nine hundred ninety-nine million, nine hundred eighty-one thousand, one hundred forty-nine".