61507321 has 2 divisors, whose sum is σ = 61507322. Its totient is φ = 61507320.

The previous prime is 61507319. The next prime is 61507333. The reversal of 61507321 is 12370516.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 58982400 + 2524921 = 7680^2 + 1589^2 .

It is a cyclic number.

It is not a de Polignac number, because 61507321 - 2¹ = 61507319 is a prime.

It is a super-3 number, since 3×61507321³ (a number of 24 digits) contains 333 as substring.

Together with 61507319, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (61607321) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 30753660 + 30753661.

It is an arithmetic number, because the mean of its divisors is an integer number (30753661).

Almost surely, 2^61507321 is an apocalyptic number.

It is an amenable number.

61507321 is a deficient number, since it is larger than the sum of its proper divisors (1).

61507321 is an equidigital number, since it uses as much as digits as its factorization.

61507321 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1260, while the sum is 25.

The square root of 61507321 is about 7842.6603267004. The cubic root of 61507321 is about 394.7380006949.

Adding to 61507321 its reverse (12370516), we get a palindrome (73877837).

The spelling of 61507321 in words is "sixty-one million, five hundred seven thousand, three hundred twenty-one".