1213521173 has 2 divisors, whose sum is σ = 1213521174. Its totient is φ = 1213521172.

The previous prime is 1213521167. The next prime is 1213521233. The reversal of 1213521173 is 3711253121.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1212641329 + 879844 = 34823^2 + 938^2 .

It is a cyclic number.

It is not a de Polignac number, because 1213521173 - 2¹² = 1213517077 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1213521163) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 606760586 + 606760587.

It is an arithmetic number, because the mean of its divisors is an integer number (606760587).

Almost surely, 2^1213521173 is an apocalyptic number.

It is an amenable number.

1213521173 is a deficient number, since it is larger than the sum of its proper divisors (1).

1213521173 is an equidigital number, since it uses as much as digits as its factorization.

1213521173 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1260, while the sum is 26.

The square root of 1213521173 is about 34835.6307966427. The cubic root of 1213521173 is about 1066.6348913169.

Adding to 1213521173 its reverse (3711253121), we get a palindrome (4924774294).

The spelling of 1213521173 in words is "one billion, two hundred thirteen million, five hundred twenty-one thousand, one hundred seventy-three".