21010173157 has 2 divisors, whose sum is σ = 21010173158. Its totient is φ = 21010173156.

The previous prime is 21010173137. The next prime is 21010173169. The reversal of 21010173157 is 75137101012.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 18749551041 + 2260622116 = 136929^2 + 47546^2 .

It is a cyclic number.

It is not a de Polignac number, because 21010173157 - 2¹¹ = 21010171109 is a prime.

It is a super-3 number, since 3×21010173157³ (a number of 32 digits) contains 333 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21010173137) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10505086578 + 10505086579.

It is an arithmetic number, because the mean of its divisors is an integer number (10505086579).

Almost surely, 2^21010173157 is an apocalyptic number.

It is an amenable number.

21010173157 is a deficient number, since it is larger than the sum of its proper divisors (1).

21010173157 is an equidigital number, since it uses as much as digits as its factorization.

21010173157 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1470, while the sum is 28.

Adding to 21010173157 its reverse (75137101012), we get a palindrome (96147274169).

The spelling of 21010173157 in words is "twenty-one billion, ten million, one hundred seventy-three thousand, one hundred fifty-seven".