216669481 has 4 divisors (see below), whose sum is σ = 247622272. Its totient is φ = 185716692.

The previous prime is 216669463. The next prime is 216669487. The reversal of 216669481 is 184966612.

216669481 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 216669481 - 2⁵ = 216669449 is a prime.

It is a super-2 number, since 2×216669481² = 93891327993618722, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (216669487) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 15476385 + ... + 15476398.

It is an arithmetic number, because the mean of its divisors is an integer number (61905568).

Almost surely, 2^216669481 is an apocalyptic number.

It is an amenable number.

216669481 is a deficient number, since it is larger than the sum of its proper divisors (30952791).

216669481 is an equidigital number, since it uses as much as digits as its factorization.

216669481 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 30952790.

The product of its digits is 124416, while the sum is 43.

The square root of 216669481 is about 14719.6970417193. The cubic root of 216669481 is about 600.6192504764.

The spelling of 216669481 in words is "two hundred sixteen million, six hundred sixty-nine thousand, four hundred eighty-one".