661622011640 has 16 divisors (see below), whose sum is σ = 1488649526280. Its totient is φ = 264648804640.

The previous prime is 661622011601. The next prime is 661622011747. The reversal of 661622011640 is 46110226166.

It is a self number, because there is not a number n which added to its sum of digits gives 661622011640.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 8270275106 + ... + 8270275185.

Almost surely, 2^661622011640 is an apocalyptic number.

It is an amenable number.

661622011640 is an abundant number, since it is smaller than the sum of its proper divisors (827027514640).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

661622011640 is a wasteful number, since it uses less digits than its factorization.

661622011640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16540550302 (or 16540550298 counting only the distinct ones).

The product of its (nonzero) digits is 20736, while the sum is 35.

The spelling of 661622011640 in words is "six hundred sixty-one billion, six hundred twenty-two million, eleven thousand, six hundred forty".