66521663402 has 16 divisors (see below), whose sum is σ = 100538172000. Its totient is φ = 33009119760.

The previous prime is 66521663279. The next prime is 66521663413. The reversal of 66521663402 is 20436612566.

It is a happy number.

It is a self number, because there is not a number n which added to its sum of digits gives 66521663402.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 718349 + ... + 805647.

It is an arithmetic number, because the mean of its divisors is an integer number (6283635750).

Almost surely, 2^66521663402 is an apocalyptic number.

66521663402 is a deficient number, since it is larger than the sum of its proper divisors (34016508598).

66521663402 is a wasteful number, since it uses less digits than its factorization.

66521663402 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 90181.

The product of its (nonzero) digits is 311040, while the sum is 41.

The spelling of 66521663402 in words is "sixty-six billion, five hundred twenty-one million, six hundred sixty-three thousand, four hundred two".