661071838640812 has 24 divisors (see below), whose sum is σ = 1173977154618912. Its totient is φ = 325656202502400.

The previous prime is 661071838640777. The next prime is 661071838640813. The reversal of 661071838640812 is 218046838170166.

It is not an unprimeable number, because it can be changed into a prime (661071838640813) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 800591389 + ... + 801416692.

It is an arithmetic number, because the mean of its divisors is an integer number (48915714775788).

Almost surely, 2^{661071838640812} is an apocalyptic number.

It is an amenable number.

661071838640812 is a deficient number, since it is larger than the sum of its proper divisors (512905315978100).

661071838640812 is a wasteful number, since it uses less digits than its factorization.

661071838640812 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1602009609 (or 1602009607 counting only the distinct ones).

The product of its (nonzero) digits is 18579456, while the sum is 61.

The spelling of 661071838640812 in words is "six hundred sixty-one trillion, seventy-one billion, eight hundred thirty-eight million, six hundred forty thousand, eight hundred twelve".