1686667037021 has 2 divisors, whose sum is σ = 1686667037022. Its totient is φ = 1686667037020.

The previous prime is 1686667036991. The next prime is 1686667037057. The reversal of 1686667037021 is 1207307666861.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1445792212921 + 240874824100 = 1202411^2 + 490790^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1686667037021 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1686667033021) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 843333518510 + 843333518511.

It is an arithmetic number, because the mean of its divisors is an integer number (843333518511).

Almost surely, 2^{1686667037021} is an apocalyptic number.

It is an amenable number.

1686667037021 is a deficient number, since it is larger than the sum of its proper divisors (1).

1686667037021 is an equidigital number, since it uses as much as digits as its factorization.

1686667037021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3048192, while the sum is 53.

The spelling of 1686667037021 in words is "one trillion, six hundred eighty-six billion, six hundred sixty-seven million, thirty-seven thousand, twenty-one".