661650010061 has 4 divisors (see below), whose sum is σ = 661832236224. Its totient is φ = 661467783900.

The previous prime is 661650010039. The next prime is 661650010069. The reversal of 661650010061 is 160010056166.

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 a de Polignac number, because none of the positive numbers 2^k-661650010061 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (661650010069) 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, 91107635 + ... + 91114896.

It is an arithmetic number, because the mean of its divisors is an integer number (165458059056).

Almost surely, 2^661650010061 is an apocalyptic number.

It is an amenable number.

661650010061 is a deficient number, since it is larger than the sum of its proper divisors (182226163).

661650010061 is a wasteful number, since it uses less digits than its factorization.

661650010061 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 182226162.

The product of its (nonzero) digits is 6480, while the sum is 32.

The spelling of 661650010061 in words is "six hundred sixty-one billion, six hundred fifty million, ten thousand, sixty-one".