667221706 has 4 divisors (see below), whose sum is σ = 1000832562. Its totient is φ = 333610852.

The previous prime is 667221701. The next prime is 667221739. The reversal of 667221706 is 607122766.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 649791081 + 17430625 = 25491^2 + 4175^2 .

It is not an unprimeable number, because it can be changed into a prime (667221701) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 166805425 + ... + 166805428.

Almost surely, 2^667221706 is an apocalyptic number.

667221706 is a deficient number, since it is larger than the sum of its proper divisors (333610856).

667221706 is a wasteful number, since it uses less digits than its factorization.

667221706 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 333610855.

The product of its (nonzero) digits is 42336, while the sum is 37.

The square root of 667221706 is about 25830.6350289729. The cubic root of 667221706 is about 873.8228332461.

The spelling of 667221706 in words is "six hundred sixty-seven million, two hundred twenty-one thousand, seven hundred six".