21240204149 has 2 divisors, whose sum is σ = 21240204150. Its totient is φ = 21240204148.

The previous prime is 21240204079. The next prime is 21240204229. The reversal of 21240204149 is 94140204212.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 14383204900 + 6856999249 = 119930^2 + 82807^2 .

It is a cyclic number.

It is not a de Polignac number, because 21240204149 - 2¹² = 21240200053 is a prime.

It is a super-2 number, since 2×21240204149² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21240204949) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10620102074 + 10620102075.

It is an arithmetic number, because the mean of its divisors is an integer number (10620102075).

Almost surely, 2^21240204149 is an apocalyptic number.

It is an amenable number.

21240204149 is a deficient number, since it is larger than the sum of its proper divisors (1).

21240204149 is an equidigital number, since it uses as much as digits as its factorization.

21240204149 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 4608, while the sum is 29.

The spelling of 21240204149 in words is "twenty-one billion, two hundred forty million, two hundred four thousand, one hundred forty-nine".