1687220973 has 18 divisors (see below), whose sum is σ = 2518261902. Its totient is φ = 1088524080.

The previous prime is 1687220963. The next prime is 1687220989. The reversal of 1687220973 is 3790227861.

1687220973 is digitally balanced in base 4, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in only one way, i.e., 964847844 + 722373129 = 31062^2 + 26877^2 .

It is not a de Polignac number, because 1687220973 - 2²⁵ = 1653666541 is a prime.

It is a super-2 number, since 2×1687220973² = 5693429223462133458, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1687220923) by changing a digit.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 88890 + ... + 106187.

It is an arithmetic number, because the mean of its divisors is an integer number (139903439).

Almost surely, 2^1687220973 is an apocalyptic number.

It is an amenable number.

1687220973 is a deficient number, since it is larger than the sum of its proper divisors (831040929).

1687220973 is a wasteful number, since it uses less digits than its factorization.

1687220973 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 195145 (or 195111 counting only the distinct ones).

The product of its (nonzero) digits is 254016, while the sum is 45.

The square root of 1687220973 is about 41075.7954639956. The cubic root of 1687220973 is about 1190.4851664327.

The spelling of 1687220973 in words is "one billion, six hundred eighty-seven million, two hundred twenty thousand, nine hundred seventy-three".