66221602 has 4 divisors (see below), whose sum is σ = 99332406. Its totient is φ = 33110800.

The previous prime is 66221569. The next prime is 66221621. The reversal of 66221602 is 20612266.

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., 62869041 + 3352561 = 7929^2 + 1831^2 .

It is a super-4 number, since 4×66221602⁴ (a number of 32 digits) contains 4444 as substring.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 16555399 + ... + 16555402.

Almost surely, 2^66221602 is an apocalyptic number.

66221602 is a deficient number, since it is larger than the sum of its proper divisors (33110804).

66221602 is a wasteful number, since it uses less digits than its factorization.

66221602 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 33110803.

The product of its (nonzero) digits is 1728, while the sum is 25.

The square root of 66221602 is about 8137.6656357951. The cubic root of 66221602 is about 404.5757931928.

Adding to 66221602 its reverse (20612266), we get a palindrome (86833868).

The spelling of 66221602 in words is "sixty-six million, two hundred twenty-one thousand, six hundred two".