216154721 has 2 divisors, whose sum is σ = 216154722. Its totient is φ = 216154720.

The previous prime is 216154717. The next prime is 216154751. The reversal of 216154721 is 127451612.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 162205696 + 53949025 = 12736^2 + 7345^2 .

It is a cyclic number.

It is not a de Polignac number, because 216154721 - 2² = 216154717 is a prime.

It is not a weakly prime, because it can be changed into another prime (216154751) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 108077360 + 108077361.

It is an arithmetic number, because the mean of its divisors is an integer number (108077361).

Almost surely, 2^216154721 is an apocalyptic number.

It is an amenable number.

216154721 is a deficient number, since it is larger than the sum of its proper divisors (1).

216154721 is an equidigital number, since it uses as much as digits as its factorization.

216154721 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3360, while the sum is 29.

The square root of 216154721 is about 14702.2012297479. The cubic root of 216154721 is about 600.1432259930.

The spelling of 216154721 in words is "two hundred sixteen million, one hundred fifty-four thousand, seven hundred twenty-one".