31420217 has 2 divisors, whose sum is σ = 31420218. Its totient is φ = 31420216.

The previous prime is 31420189. The next prime is 31420223. The reversal of 31420217 is 71202413.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 29822521 + 1597696 = 5461^2 + 1264^2 .

It is an emirp because it is prime and its reverse (71202413) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 31420217 - 2⁶ = 31420153 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (31420517) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15710108 + 15710109.

It is an arithmetic number, because the mean of its divisors is an integer number (15710109).

Almost surely, 2^31420217 is an apocalyptic number.

It is an amenable number.

31420217 is a deficient number, since it is larger than the sum of its proper divisors (1).

31420217 is an equidigital number, since it uses as much as digits as its factorization.

31420217 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 336, while the sum is 20.

The square root of 31420217 is about 5605.3739393550. The cubic root of 31420217 is about 315.5511205312.

The spelling of 31420217 in words is "thirty-one million, four hundred twenty thousand, two hundred seventeen".