1687520517221 has 12 divisors (see below), whose sum is σ = 2141491714560. Its totient is φ = 1314951051960.

The previous prime is 1687520517211. The next prime is 1687520517223. The reversal of 1687520517221 is 1227150257861.

It is a happy number.

It is not a de Polignac number, because 1687520517221 - 2⁶ = 1687520517157 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1687520517223) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1565417381 + ... + 1565418458.

It is an arithmetic number, because the mean of its divisors is an integer number (178457642880).

Almost surely, 2^{1687520517221} is an apocalyptic number.

1687520517221 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1687520517221 is a deficient number, since it is larger than the sum of its proper divisors (453971197339).

1687520517221 is a wasteful number, since it uses less digits than its factorization.

1687520517221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3130835864 (or 3130835857 counting only the distinct ones).

The product of its (nonzero) digits is 470400, while the sum is 47.

The spelling of 1687520517221 in words is "one trillion, six hundred eighty-seven billion, five hundred twenty million, five hundred seventeen thousand, two hundred twenty-one".