21515420155069 has 2 divisors, whose sum is σ = 21515420155070. Its totient is φ = 21515420155068.

The previous prime is 21515420155003. The next prime is 21515420155087. The reversal of 21515420155069 is 96055102451512.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 15769873476900 + 5745546678169 = 3971130^2 + 2396987^2 .

It is a cyclic number.

It is not a de Polignac number, because 21515420155069 - 2¹¹ = 21515420153021 is a prime.

It is a super-2 number, since 2×21515420155069² (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 (21515420155169) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10757710077534 + 10757710077535.

It is an arithmetic number, because the mean of its divisors is an integer number (10757710077535).

Almost surely, 2^{21515420155069} is an apocalyptic number.

It is an amenable number.

21515420155069 is a deficient number, since it is larger than the sum of its proper divisors (1).

21515420155069 is an equidigital number, since it uses as much as digits as its factorization.

21515420155069 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 540000, while the sum is 46.

The spelling of 21515420155069 in words is "twenty-one trillion, five hundred fifteen billion, four hundred twenty million, one hundred fifty-five thousand, sixty-nine".