21123173036237 has 2 divisors, whose sum is σ = 21123173036238. Its totient is φ = 21123173036236.

The previous prime is 21123173036183. The next prime is 21123173036327. The reversal of 21123173036237 is 73263037132112.

Together with next prime (21123173036327) it forms an Ormiston pair, because they use the same digits, order apart.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 21122655291721 + 517744516 = 4595939^2 + 22754^2 .

It is a cyclic number.

It is not a de Polignac number, because 21123173036237 - 2¹² = 21123173032141 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21123173036194 and 21123173036203.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21123173036737) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10561586518118 + 10561586518119.

It is an arithmetic number, because the mean of its divisors is an integer number (10561586518119).

Almost surely, 2^{21123173036237} is an apocalyptic number.

It is an amenable number.

21123173036237 is a deficient number, since it is larger than the sum of its proper divisors (1).

21123173036237 is an equidigital number, since it uses as much as digits as its factorization.

21123173036237 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 190512, while the sum is 41.

The spelling of 21123173036237 in words is "twenty-one trillion, one hundred twenty-three billion, one hundred seventy-three million, thirty-six thousand, two hundred thirty-seven".