97218391 has 2 divisors, whose sum is σ = 97218392. Its totient is φ = 97218390.

The previous prime is 97218367. The next prime is 97218397. The reversal of 97218391 is 19381279.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-97218391 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (97218397) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 48609195 + 48609196.

It is an arithmetic number, because the mean of its divisors is an integer number (48609196).

Almost surely, 2^97218391 is an apocalyptic number.

97218391 is a deficient number, since it is larger than the sum of its proper divisors (1).

97218391 is an equidigital number, since it uses as much as digits as its factorization.

97218391 is an evil number, because the sum of its binary digits is even.

The product of its digits is 27216, while the sum is 40.

The square root of 97218391 is about 9859.9386914930. The cubic root of 97218391 is about 459.8146559547.

The spelling of 97218391 in words is "ninety-seven million, two hundred eighteen thousand, three hundred ninety-one".