135208546021 has 2 divisors, whose sum is σ = 135208546022. Its totient is φ = 135208546020.

The previous prime is 135208545971. The next prime is 135208546027. The reversal of 135208546021 is 120645802531.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 113845508100 + 21363037921 = 337410^2 + 146161^2 .

It is a cyclic number.

It is not a de Polignac number, because 135208546021 - 2²⁷ = 135074328293 is a prime.

It is a super-2 number, since 2×135208546021² (a number of 23 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (135208546027) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 67604273010 + 67604273011.

It is an arithmetic number, because the mean of its divisors is an integer number (67604273011).

Almost surely, 2^135208546021 is an apocalyptic number.

It is an amenable number.

135208546021 is a deficient number, since it is larger than the sum of its proper divisors (1).

135208546021 is an equidigital number, since it uses as much as digits as its factorization.

135208546021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 57600, while the sum is 37.

The spelling of 135208546021 in words is "one hundred thirty-five billion, two hundred eight million, five hundred forty-six thousand, twenty-one".