21115135325077 has 2 divisors, whose sum is σ = 21115135325078. Its totient is φ = 21115135325076.

The previous prime is 21115135324981. The next prime is 21115135325087. The reversal of 21115135325077 is 77052353151112.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20699669996721 + 415465328356 = 4549689^2 + 644566^2 .

It is a cyclic number.

It is not a de Polignac number, because 21115135325077 - 2¹⁵ = 21115135292309 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21115135325087) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10557567662538 + 10557567662539.

It is an arithmetic number, because the mean of its divisors is an integer number (10557567662539).

Almost surely, 2^{21115135325077} is an apocalyptic number.

It is an amenable number.

21115135325077 is a deficient number, since it is larger than the sum of its proper divisors (1).

21115135325077 is an equidigital number, since it uses as much as digits as its factorization.

21115135325077 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 220500, while the sum is 43.

Adding to 21115135325077 its reverse (77052353151112), we get a palindrome (98167488476189).

The spelling of 21115135325077 in words is "twenty-one trillion, one hundred fifteen billion, one hundred thirty-five million, three hundred twenty-five thousand, seventy-seven".