21533502525181 has 2 divisors, whose sum is σ = 21533502525182. Its totient is φ = 21533502525180.

The previous prime is 21533502525167. The next prime is 21533502525277. The reversal of 21533502525181 is 18152520533512.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 21384529684281 + 148972840900 = 4624341^2 + 385970^2 .

It is a cyclic number.

It is not a de Polignac number, because 21533502525181 - 2⁷ = 21533502525053 is a prime.

It is a super-2 number, since 2×21533502525181² (a number of 27 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21533502525881) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10766751262590 + 10766751262591.

It is an arithmetic number, because the mean of its divisors is an integer number (10766751262591).

Almost surely, 2^{21533502525181} is an apocalyptic number.

It is an amenable number.

21533502525181 is a deficient number, since it is larger than the sum of its proper divisors (1).

21533502525181 is an equidigital number, since it uses as much as digits as its factorization.

21533502525181 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 360000, while the sum is 43.

The spelling of 21533502525181 in words is "twenty-one trillion, five hundred thirty-three billion, five hundred two million, five hundred twenty-five thousand, one hundred eighty-one".