215481389 has 2 divisors, whose sum is σ = 215481390. Its totient is φ = 215481388.

The previous prime is 215481367. The next prime is 215481419. The reversal of 215481389 is 983184512.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 131905225 + 83576164 = 11485^2 + 9142^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-215481389 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 (215481349) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 107740694 + 107740695.

It is an arithmetic number, because the mean of its divisors is an integer number (107740695).

Almost surely, 2^215481389 is an apocalyptic number.

It is an amenable number.

215481389 is a deficient number, since it is larger than the sum of its proper divisors (1).

215481389 is an equidigital number, since it uses as much as digits as its factorization.

215481389 is an evil number, because the sum of its binary digits is even.

The product of its digits is 69120, while the sum is 41.

The square root of 215481389 is about 14679.2843490410. The cubic root of 215481389 is about 599.5194198035.

The spelling of 215481389 in words is "two hundred fifteen million, four hundred eighty-one thousand, three hundred eighty-nine".