661220053597 has 2 divisors, whose sum is σ = 661220053598. Its totient is φ = 661220053596.

The previous prime is 661220053577. The next prime is 661220053633. The reversal of 661220053597 is 795350022166.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 652199992921 + 9020060676 = 807589^2 + 94974^2 .

It is a cyclic number.

It is not a de Polignac number, because 661220053597 - 2³⁹ = 111464239709 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (661220053577) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 330610026798 + 330610026799.

It is an arithmetic number, because the mean of its divisors is an integer number (330610026799).

Almost surely, 2^661220053597 is an apocalyptic number.

It is an amenable number.

661220053597 is a deficient number, since it is larger than the sum of its proper divisors (1).

661220053597 is an equidigital number, since it uses as much as digits as its factorization.

661220053597 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 680400, while the sum is 46.

The spelling of 661220053597 in words is "six hundred sixty-one billion, two hundred twenty million, fifty-three thousand, five hundred ninety-seven".