1686634297921 has 8 divisors (see below), whose sum is σ = 1706378471424. Its totient is φ = 1666991118240.

The previous prime is 1686634297903. The next prime is 1686634297939. The reversal of 1686634297921 is 1297924366861.

It is an interprime number because it is at equal distance from previous prime (1686634297903) and next prime (1686634297939).

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 1686634297921 - 2²⁷ = 1686500080193 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1686634217921) 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, 25214860 + ... + 25281661.

It is an arithmetic number, because the mean of its divisors is an integer number (213297308928).

Almost surely, 2^{1686634297921} is an apocalyptic number.

It is an amenable number.

1686634297921 is a deficient number, since it is larger than the sum of its proper divisors (19744173503).

1686634297921 is a wasteful number, since it uses less digits than its factorization.

1686634297921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 50496911.

The product of its digits is 47029248, while the sum is 64.

The spelling of 1686634297921 in words is "one trillion, six hundred eighty-six billion, six hundred thirty-four million, two hundred ninety-seven thousand, nine hundred twenty-one".