66821221090 has 32 divisors (see below), whose sum is σ = 129561155136. Its totient is φ = 24666586560.

The previous prime is 66821221031. The next prime is 66821221127. The reversal of 66821221090 is 9012212866.

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, 508285 + ... + 626095.

It is an arithmetic number, because the mean of its divisors is an integer number (4048786098).

Almost surely, 2^66821221090 is an apocalyptic number.

66821221090 is a deficient number, since it is larger than the sum of its proper divisors (62739934046).

66821221090 is a wasteful number, since it uses less digits than its factorization.

66821221090 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 122194.

The product of its (nonzero) digits is 20736, while the sum is 37.

The spelling of 66821221090 in words is "sixty-six billion, eight hundred twenty-one million, two hundred twenty-one thousand, ninety".