661246321 has 4 divisors (see below), whose sum is σ = 661394944. Its totient is φ = 661097700.

The previous prime is 661246259. The next prime is 661246349. The reversal of 661246321 is 123642166.

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, and also an emirpimes, since its reverse is a distinct semiprime: 123642166 = 2 ⋅61821083.

It is a cyclic number.

It is not a de Polignac number, because 661246321 - 2¹³ = 661238129 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (661246361) 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, 67425 + ... + 76606.

It is an arithmetic number, because the mean of its divisors is an integer number (165348736).

Almost surely, 2^661246321 is an apocalyptic number.

It is an amenable number.

661246321 is a deficient number, since it is larger than the sum of its proper divisors (148623).

661246321 is a wasteful number, since it uses less digits than its factorization.

661246321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 148622.

The product of its digits is 10368, while the sum is 31.

The square root of 661246321 is about 25714.7102064169. The cubic root of 661246321 is about 871.2064650714.

Adding to 661246321 its reverse (123642166), we get a palindrome (784888487).

The spelling of 661246321 in words is "six hundred sixty-one million, two hundred forty-six thousand, three hundred twenty-one".