661684223 has 4 divisors (see below), whose sum is σ = 661796808. Its totient is φ = 661571640.

The previous prime is 661684211. The next prime is 661684241. The reversal of 661684223 is 322486166.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 322486166 = 2 ⋅161243083.

It is a cyclic number.

It is not a de Polignac number, because 661684223 - 2⁴ = 661684207 is a prime.

It is a super-2 number, since 2×661684223² = 875652021934227458, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (661684123) 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, 46961 + ... + 59402.

It is an arithmetic number, because the mean of its divisors is an integer number (165449202).

Almost surely, 2^661684223 is an apocalyptic number.

661684223 is a deficient number, since it is larger than the sum of its proper divisors (112585).

661684223 is a wasteful number, since it uses less digits than its factorization.

661684223 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 112584.

The product of its digits is 82944, while the sum is 38.

The square root of 661684223 is about 25723.2234177601. The cubic root of 661684223 is about 871.3987377829.

The spelling of 661684223 in words is "six hundred sixty-one million, six hundred eighty-four thousand, two hundred twenty-three".