1687621473 has 20 divisors (see below), whose sum is σ = 2579648368. Its totient is φ = 1098914040.

The previous prime is 1687621457. The next prime is 1687621513. The reversal of 1687621473 is 3741267861.

1687621473 is a `hidden beast` number, since 16 + 8 + 7 + 621 + 4 + 7 + 3 = 666.

It is not a de Polignac number, because 1687621473 - 2⁴ = 1687621457 is a prime.

It is a super-2 number, since 2×1687621473² = 5696132472261379458, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1687622473) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 238783 + ... + 245748.

Almost surely, 2^1687621473 is an apocalyptic number.

It is an amenable number.

1687621473 is a deficient number, since it is larger than the sum of its proper divisors (892026895).

1687621473 is an equidigital number, since it uses as much as digits as its factorization.

1687621473 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 484586 (or 484577 counting only the distinct ones).

The product of its digits is 338688, while the sum is 45.

The square root of 1687621473 is about 41080.6703085527. The cubic root of 1687621473 is about 1190.5793551601.

The spelling of 1687621473 in words is "one billion, six hundred eighty-seven million, six hundred twenty-one thousand, four hundred seventy-three".