31553212217 has 2 divisors, whose sum is σ = 31553212218. Its totient is φ = 31553212216.

The previous prime is 31553212211. The next prime is 31553212241. The reversal of 31553212217 is 71221235513.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 19615683136 + 11937529081 = 140056^2 + 109259^2 .

It is an emirp because it is prime and its reverse (71221235513) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 31553212217 - 2¹² = 31553208121 is a prime.

It is a super-2 number, since 2×31553212217² (a number of 22 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (31553212211) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15776606108 + 15776606109.

It is an arithmetic number, because the mean of its divisors is an integer number (15776606109).

Almost surely, 2^31553212217 is an apocalyptic number.

It is an amenable number.

31553212217 is a deficient number, since it is larger than the sum of its proper divisors (1).

31553212217 is an equidigital number, since it uses as much as digits as its factorization.

31553212217 is an evil number, because the sum of its binary digits is even.

The product of its digits is 12600, while the sum is 32.

The spelling of 31553212217 in words is "thirty-one billion, five hundred fifty-three million, two hundred twelve thousand, two hundred seventeen".