661546303421 has 2 divisors, whose sum is σ = 661546303422. Its totient is φ = 661546303420.

The previous prime is 661546303403. The next prime is 661546303469. The reversal of 661546303421 is 124303645166.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 639408136900 + 22138166521 = 799630^2 + 148789^2 .

It is a cyclic number.

It is not a de Polignac number, because 661546303421 - 2¹⁰ = 661546302397 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (661546303721) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 330773151710 + 330773151711.

It is an arithmetic number, because the mean of its divisors is an integer number (330773151711).

Almost surely, 2^661546303421 is an apocalyptic number.

It is an amenable number.

661546303421 is a deficient number, since it is larger than the sum of its proper divisors (1).

661546303421 is an equidigital number, since it uses as much as digits as its factorization.

661546303421 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 311040, while the sum is 41.

Adding to 661546303421 its reverse (124303645166), we get a palindrome (785849948587).

The spelling of 661546303421 in words is "six hundred sixty-one billion, five hundred forty-six million, three hundred three thousand, four hundred twenty-one".