216450391 has 2 divisors, whose sum is σ = 216450392. Its totient is φ = 216450390.

The previous prime is 216450371. The next prime is 216450419. The reversal of 216450391 is 193054612.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 216450391 - 2¹³ = 216442199 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (216450301) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 108225195 + 108225196.

It is an arithmetic number, because the mean of its divisors is an integer number (108225196).

Almost surely, 2^216450391 is an apocalyptic number.

216450391 is a deficient number, since it is larger than the sum of its proper divisors (1).

216450391 is an equidigital number, since it uses as much as digits as its factorization.

216450391 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 6480, while the sum is 31.

The square root of 216450391 is about 14712.2530905365. The cubic root of 216450391 is about 600.4167391841.

The spelling of 216450391 in words is "two hundred sixteen million, four hundred fifty thousand, three hundred ninety-one".