221664550642 has 4 divisors (see below), whose sum is σ = 332496825966. Its totient is φ = 110832275320.

The previous prime is 221664550631. The next prime is 221664550733. The reversal of 221664550642 is 246055466122.

It is a happy number.

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., 221634749961 + 29800681 = 470781^2 + 5459^2 .

It is a super-2 number, since 2×221664550642² (a number of 23 digits) contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 55416137659 + ... + 55416137662.

Almost surely, 2^221664550642 is an apocalyptic number.

221664550642 is a deficient number, since it is larger than the sum of its proper divisors (110832275324).

221664550642 is a wasteful number, since it uses less digits than its factorization.

221664550642 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 110832275323.

The product of its (nonzero) digits is 691200, while the sum is 43.

The spelling of 221664550642 in words is "two hundred twenty-one billion, six hundred sixty-four million, five hundred fifty thousand, six hundred forty-two".