651561165566 has 4 divisors (see below), whose sum is σ = 977341748352. Its totient is φ = 325780582782.

The previous prime is 651561165559. The next prime is 651561165617. The reversal of 651561165566 is 665561165156.

It is a semiprime because it is the product of two primes.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 162890291390 + ... + 162890291393.

It is an arithmetic number, because the mean of its divisors is an integer number (244335437088).

Almost surely, 2^651561165566 is an apocalyptic number.

651561165566 is a deficient number, since it is larger than the sum of its proper divisors (325780582786).

651561165566 is a wasteful number, since it uses less digits than its factorization.

651561165566 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 325780582785.

The product of its digits is 4860000, while the sum is 53.

The spelling of 651561165566 in words is "six hundred fifty-one billion, five hundred sixty-one million, one hundred sixty-five thousand, five hundred sixty-six".