661626067216 has 15 divisors (see below), whose sum is σ = 1281906809143. Its totient is φ = 330811406800.

The previous prime is 661626067183. The next prime is 661626067303. The reversal of 661626067216 is 612760626166.

The square root of 661626067216 is 813404.

It is a perfect power (a square), and thus also a powerful number.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 661626067216.

It is an unprimeable number.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 3151941 + ... + 3355291.

Almost surely, 2^661626067216 is an apocalyptic number.

661626067216 is the 813404-th square number.

It is an amenable number.

661626067216 is a deficient number, since it is larger than the sum of its proper divisors (620280741927).

661626067216 is an frugal number, since it uses more digits than its factorization.

661626067216 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 406710 (or 203353 counting only the distinct ones).

The product of its (nonzero) digits is 1306368, while the sum is 49.

Multiplying 661626067216 by its sum of digits (49), we get a square (32419677293584 = 5693828²).

The spelling of 661626067216 in words is "six hundred sixty-one billion, six hundred twenty-six million, sixty-seven thousand, two hundred sixteen".