21156211753 has 2 divisors, whose sum is σ = 21156211754. Its totient is φ = 21156211752.

The previous prime is 21156211717. The next prime is 21156211757. The reversal of 21156211753 is 35711265112.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 13296857344 + 7859354409 = 115312^2 + 88653^2 .

It is a cyclic number.

It is not a de Polignac number, because 21156211753 - 2¹³ = 21156203561 is a prime.

It is not a weakly prime, because it can be changed into another prime (21156211757) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10578105876 + 10578105877.

It is an arithmetic number, because the mean of its divisors is an integer number (10578105877).

Almost surely, 2^21156211753 is an apocalyptic number.

It is an amenable number.

21156211753 is a deficient number, since it is larger than the sum of its proper divisors (1).

21156211753 is an equidigital number, since it uses as much as digits as its factorization.

21156211753 is an evil number, because the sum of its binary digits is even.

The product of its digits is 12600, while the sum is 34.

Adding to 21156211753 its reverse (35711265112), we get a palindrome (56867476865).

The spelling of 21156211753 in words is "twenty-one billion, one hundred fifty-six million, two hundred eleven thousand, seven hundred fifty-three".