661201057201 has 4 divisors (see below), whose sum is σ = 661202983152. Its totient is φ = 661199131252.

The previous prime is 661201057183. The next prime is 661201057207. The reversal of 661201057201 is 102750102166.

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.

It is a cyclic number.

It is not a de Polignac number, because 661201057201 - 2¹⁷ = 661200926129 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (661201057207) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 292315 + ... + 1186528.

It is an arithmetic number, because the mean of its divisors is an integer number (165300745788).

Almost surely, 2^661201057201 is an apocalyptic number.

It is an amenable number.

661201057201 is a deficient number, since it is larger than the sum of its proper divisors (1925951).

661201057201 is a wasteful number, since it uses less digits than its factorization.

661201057201 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1925950.

The product of its (nonzero) digits is 5040, while the sum is 31.

Adding to 661201057201 its reverse (102750102166), we get a palindrome (763951159367).

The spelling of 661201057201 in words is "six hundred sixty-one billion, two hundred one million, fifty-seven thousand, two hundred one".