66399651505 has 16 divisors (see below), whose sum is σ = 87506568000. Its totient is φ = 47966551360.

The previous prime is 66399651473. The next prime is 66399651523. The reversal of 66399651505 is 50515699366.

It is not a de Polignac number, because 66399651505 - 2⁵ = 66399651473 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (55).

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4043035 + ... + 4059424.

It is an arithmetic number, because the mean of its divisors is an integer number (5469160500).

Almost surely, 2^66399651505 is an apocalyptic number.

It is an amenable number.

66399651505 is a deficient number, since it is larger than the sum of its proper divisors (21106916495).

66399651505 is a wasteful number, since it uses less digits than its factorization.

66399651505 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8102624.

The product of its (nonzero) digits is 6561000, while the sum is 55.

The spelling of 66399651505 in words is "sixty-six billion, three hundred ninety-nine million, six hundred fifty-one thousand, five hundred five".