61660321 has 4 divisors (see below), whose sum is σ = 61677700. Its totient is φ = 61642944.

The previous prime is 61660307. The next prime is 61660331. The reversal of 61660321 is 12306616.

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

It can be written as a sum of positive squares in 2 ways, for example, as 5934096 + 55726225 = 2436^2 + 7465^2 .

It is a cyclic number.

It is not a de Polignac number, because 61660321 - 2⁵ = 61660289 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (61660331) 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, 1236 + ... + 11173.

It is an arithmetic number, because the mean of its divisors is an integer number (15419425).

Almost surely, 2^61660321 is an apocalyptic number.

It is an amenable number.

61660321 is a deficient number, since it is larger than the sum of its proper divisors (17379).

61660321 is a wasteful number, since it uses less digits than its factorization.

61660321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17378.

The product of its (nonzero) digits is 1296, while the sum is 25.

The square root of 61660321 is about 7852.4086113752. The cubic root of 61660321 is about 395.0650344235.

Adding to 61660321 its reverse (12306616), we get a palindrome (73966937).

The spelling of 61660321 in words is "sixty-one million, six hundred sixty thousand, three hundred twenty-one".