21112220985637 has 2 divisors, whose sum is σ = 21112220985638. Its totient is φ = 21112220985636.

The previous prime is 21112220985619. The next prime is 21112220985671. The reversal of 21112220985637 is 73658902221112.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20215940333796 + 896280651841 = 4496214^2 + 946721^2 .

It is a cyclic number.

It is not a de Polignac number, because 21112220985637 - 2⁴³ = 12316127963429 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21112220785637) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10556110492818 + 10556110492819.

It is an arithmetic number, because the mean of its divisors is an integer number (10556110492819).

Almost surely, 2^{21112220985637} is an apocalyptic number.

It is an amenable number.

21112220985637 is a deficient number, since it is larger than the sum of its proper divisors (1).

21112220985637 is an equidigital number, since it uses as much as digits as its factorization.

21112220985637 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 725760, while the sum is 49.

The spelling of 21112220985637 in words is "twenty-one trillion, one hundred twelve billion, two hundred twenty million, nine hundred eighty-five thousand, six hundred thirty-seven".