21155002535749 has 2 divisors, whose sum is σ = 21155002535750. Its totient is φ = 21155002535748.

The previous prime is 21155002535687. The next prime is 21155002535783. The reversal of 21155002535749 is 94753520055112.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19943208871524 + 1211793664225 = 4465782^2 + 1100815^2 .

It is a cyclic number.

It is not a de Polignac number, because 21155002535749 - 2¹⁷ = 21155002404677 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21155002535449) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10577501267874 + 10577501267875.

It is an arithmetic number, because the mean of its divisors is an integer number (10577501267875).

Almost surely, 2^{21155002535749} is an apocalyptic number.

It is an amenable number.

21155002535749 is a deficient number, since it is larger than the sum of its proper divisors (1).

21155002535749 is an equidigital number, since it uses as much as digits as its factorization.

21155002535749 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1890000, while the sum is 49.

The spelling of 21155002535749 in words is "twenty-one trillion, one hundred fifty-five billion, two million, five hundred thirty-five thousand, seven hundred forty-nine".