21530013149 has 2 divisors, whose sum is σ = 21530013150. Its totient is φ = 21530013148.

The previous prime is 21530013133. The next prime is 21530013157. The reversal of 21530013149 is 94131003512.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 15238668025 + 6291345124 = 123445^2 + 79318^2 .

It is a cyclic number.

It is not a de Polignac number, because 21530013149 - 2⁴ = 21530013133 is a prime.

It is a super-2 number, since 2×21530013149² (a number of 21 digits) contains 22 as substring.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21430013149) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10765006574 + 10765006575.

It is an arithmetic number, because the mean of its divisors is an integer number (10765006575).

Almost surely, 2^21530013149 is an apocalyptic number.

It is an amenable number.

21530013149 is a deficient number, since it is larger than the sum of its proper divisors (1).

21530013149 is an equidigital number, since it uses as much as digits as its factorization.

21530013149 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3240, while the sum is 29.

The spelling of 21530013149 in words is "twenty-one billion, five hundred thirty million, thirteen thousand, one hundred forty-nine".