651561656138 has 8 divisors (see below), whose sum is σ = 977546069220. Its totient is φ = 325712966400.

The previous prime is 651561656113. The next prime is 651561656143. The reversal of 651561656138 is 831656165156.

It can be written as a sum of positive squares in 2 ways, for example, as 649544119249 + 2017536889 = 805943^2 + 44917^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 651561656138.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 33918833 + ... + 33938036.

Almost surely, 2^651561656138 is an apocalyptic number.

651561656138 is a deficient number, since it is larger than the sum of its proper divisors (325984413082).

651561656138 is a wasteful number, since it uses less digits than its factorization.

651561656138 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 67861672.

The product of its digits is 3888000, while the sum is 53.

The spelling of 651561656138 in words is "six hundred fifty-one billion, five hundred sixty-one million, six hundred fifty-six thousand, one hundred thirty-eight".