1971972991786 has 16 divisors (see below), whose sum is σ = 3388156121664. Its totient is φ = 843223533984.

The previous prime is 1971972991759. The next prime is 1971972991787. The reversal of 1971972991786 is 6871992791791.

It is not an unprimeable number, because it can be changed into a prime (1971972991787) 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, 158972595 + ... + 158984998.

It is an arithmetic number, because the mean of its divisors is an integer number (211759757604).

Almost surely, 2^{1971972991786} is an apocalyptic number.

1971972991786 is a deficient number, since it is larger than the sum of its proper divisors (1416183129878).

1971972991786 is a wasteful number, since it uses less digits than its factorization.

1971972991786 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 317958045.

The product of its digits is 216040608, while the sum is 76.

The spelling of 1971972991786 in words is "one trillion, nine hundred seventy-one billion, nine hundred seventy-two million, nine hundred ninety-one thousand, seven hundred eighty-six".